1<!DOCTYPE html> 2<head> 3<title>Android ANDROID_VERSION Compatibility Definition</title> 4<link rel="stylesheet" type="text/css" href="android-cdd.css"/> 5</head> 6 7<body> 8 9<h6>Table of Contents</h6> 10 11<div id="toc"> 12 13<div id="toc_left"> 14 15<p class="toc_h1"><a href="#1_introduction">1. Introduction</a></p> 16 17<p class="toc_h1"><a href="#2_device_types">2. Device Types</a></p> 18 19<p class="toc_h2"><a href="#2_1_device_configurations">2.1 Device Configurations</a></p> 20 21<p class="toc_h1"><a href="#3_software">3. Software</a></p> 22 23<p class="toc_h2"><a href="#3_1_managed_api_compatibility">3.1. Managed API Compatibility</a></p> 24 25<p class="toc_h2"><a href="#3_2_soft_api_compatibility">3.2. Soft API Compatibility</a></p> 26 27<p class="toc_h3"><a href="#3_2_1_permissions">3.2.1. Permissions</a></p> 28 29<p class="toc_h3"><a href="#3_2_2_build_parameters">3.2.2. Build Parameters</a></p> 30 31<p class="toc_h3"><a href="#3_2_3_intent_compatibility">3.2.3. Intent Compatibility</a></p> 32 33<p class="toc_h4"><a href="#3_2_3_1_core_application_intents">3.2.3.1. Core Application Intents</a></p> 34 35<p class="toc_h4"><a href="#3_2_3_2_intent_resolution">3.2.3.2. Intent Resolution</a></p> 36 37<p class="toc_h4"><a href="#3_2_3_3_intent_namespaces">3.2.3.3. Intent Namespaces</a></p> 38 39<p class="toc_h4"><a href="#3_2_3_4_broadcast_intents">3.2.3.4. Broadcast Intents</a></p> 40 41<p class="toc_h4"><a href="#3_2_3_5_default_app_settings">3.2.3.5. Default App Settings</a></p> 42 43<p class="toc_h2"><a href="#3_3_native_api_compatibility">3.3. Native API Compatibility</a></p> 44 45<p class="toc_h3"><a href="#3_3_1_application_binary_interfaces">3.3.1. Application Binary Interfaces</a></p> 46 47<p class="toc_h3"><a href="#3_3_2_32-bit_arm_native_code_compatibility">3.3.2. 32-bit ARM Native Code Compatibility</a></p> 48 49<p class="toc_h2"><a href="#3_4_web_compatibility">3.4. Web Compatibility</a></p> 50 51<p class="toc_h3"><a href="#3_4_1_webview_compatibility">3.4.1. WebView Compatibility</a></p> 52 53<p class="toc_h3"><a href="#3_4_2_browser_compatibility">3.4.2. Browser Compatibility</a></p> 54 55<p class="toc_h2"><a href="#3_5_api_behavioral_compatibility">3.5. API Behavioral Compatibility</a></p> 56 57<p class="toc_h2"><a href="#3_6_api_namespaces">3.6. API Namespaces</a></p> 58 59<p class="toc_h2"><a href="#3_7_runtime_compatibility">3.7. Runtime Compatibility</a></p> 60 61<p class="toc_h2"><a href="#3_8_user_interface_compatibility">3.8. User Interface Compatibility</a></p> 62 63<p class="toc_h3"><a href="#3_8_1_launcher_home_screen">3.8.1. Launcher (Home Screen)</a></p> 64 65<p class="toc_h3"><a href="#3_8_2_widgets">3.8.2. Widgets</a></p> 66 67<p class="toc_h3"><a href="#3_8_3_notifications">3.8.3. Notifications</a></p> 68 69<p class="toc_h3"><a href="#3_8_4_search">3.8.4. Search</a></p> 70 71<p class="toc_h3"><a href="#3_8_5_toasts">3.8.5. Toasts</a></p> 72 73<p class="toc_h3"><a href="#3_8_6_themes">3.8.6. Themes</a></p> 74 75<p class="toc_h3"><a href="#3_8_7_live_wallpapers">3.8.7. Live Wallpapers</a></p> 76 77<p class="toc_h3"><a href="#3_8_8_activity_switching">3.8.8. Activity Switching</a></p> 78 79<p class="toc_h3"><a href="#3_8_9_input_management">3.8.9. Input Management</a></p> 80 81<p class="toc_h3"><a href="#3_8_10_lock_screen_media_control">3.8.10. Lock Screen Media Control</a></p> 82 83<p class="toc_h3"><a href="#3_8_11_dreams">3.8.11. Dreams</a></p> 84 85<p class="toc_h3"><a href="#3_8_12_location">3.8.12. Location</a></p> 86 87</div> 88 89<div id="toc_right"> 90 91 92<p class="toc_h3"><a href="#3_8_13_unicode_and_font">3.8.13. Unicode and Font</a></p> 93 94<p class="toc_h2"><a href="#3_9_device_administration">3.9. Device Administration</a></p> 95 96<p class="toc_h3"><a href="#3_9_1_device_provisioning">3.9.1 Device Provisioning</a></p> 97 98<p class="toc_h4"><a href="#3_9_1_2_device_owner_provisioning">3.9.1.1 Device Owner provisioning</a></p> 99 100<p class="toc_h4"><a href="#3_9_1_2_managed_profile_provisioning">3.9.1.2 Managed profile provisioning</a></p> 101 102<p class="toc_h3"><a href="#3_9_2_managed_profile_support">3.9.2. Managed Profile Support</a></p> 103 104 105<p class="toc_h2"><a href="#3_10_accessibility">3.10. Accessibility</a></p> 106 107<p class="toc_h2"><a href="#3_11_text-to-speech">3.11. Text-to-Speech</a></p> 108 109<p class="toc_h2"><a href="#3_12_tv_input_framework">3.12. TV Input Framework</a></p> 110 111<p class="toc_h3"><a href="#3_12_1_tv_app">3.12.1. TV App</a></p> 112 113<p class="toc_h4"><a href="#3_12_1_1_electronic_program_guide">3.12.1.1. Electronic Program Guide</a></p> 114 115<p class="toc_h4"><a href="#3_12_1_2_navigation">3.12.1.2. Navigation</a></p> 116 117<p class="toc_h4"><a href="#3_12_1_3_tv_input_app_linking">3.12.1.3. TV input app linking</a></p> 118 119<p class="toc_h1"><a href="#4_application_packaging_compatibility">4. Application Packaging Compatibility</a></p> 120 121<p class="toc_h1"><a href="#5_multimedia_compatibility">5. Multimedia Compatibility</a></p> 122 123<p class="toc_h2"><a href="#5_1_media_codecs">5.1. Media Codecs</a></p> 124 125<p class="toc_h3"><a href="#5_1_1_audio_codecs">5.1.1. Audio Codecs</a></p> 126 127<p class="toc_h3"><a href="#5_1_2_image_codecs">5.1.2. Image Codecs</a></p> 128 129<p class="toc_h3"><a href="#5_1_3_video_codecs">5.1.3. Video Codecs</a></p> 130 131<p class="toc_h2"><a href="#5_2_video_encoding">5.2. Video Encoding</a></p> 132 133<p class="toc_h2"><a href="#5_3_video_decoding">5.3. Video Decoding</a></p> 134 135<p class="toc_h2"><a href="#5_4_audio_recording">5.4. Audio Recording</a></p> 136 137<p class="toc_h3"><a href="#5_4_1_raw_audio_capture">5.4.1. Raw Audio Capture</a></p> 138 139<p class="toc_h3"><a href="#5_4_2_capture_for_voice_recognition">5.4.2. Capture for Voice Recognition</a></p> 140 141<p class="toc_h3"><a href="#5_4_3_capture_for_rerouting_of_playback">5.4.3. Capture for Rerouting of Playback</a></p> 142 143<p class="toc_h2"><a href="#5_5_audio_playback">5.5. Audio Playback</a></p> 144 145<p class="toc_h3"><a href="#5_5_1_raw_audio_playback">5.5.1. Raw Audio Playback</a></p> 146 147<p class="toc_h3"><a href="#5_5_2_audio_effects">5.5.2. Audio Effects</a></p> 148 149<p class="toc_h3"><a href="#5_5_3_audio_output_volume">5.5.3. Audio Output Volume</a></p> 150 151<p class="toc_h2"><a href="#5_6_audio_latency">5.6. Audio Latency</a></p> 152 153<p class="toc_h2"><a href="#5_7_network_protocols">5.7. Network Protocols</a></p> 154 155<p class="toc_h2"><a href="#5_8_secure_media">5.8. Secure Media</a></p> 156 157<p class="toc_h2"><a href="#5_9_midi">5.9. Musical Instrument Digital Interface (MIDI)</a></p> 158 159<p class="toc_h2"><a href="#5_10_pro_audio">5.10. Professional Audio</a></p> 160 161</div> 162 163<div style="clear: both; page-break-after:always; height:1px"></div> 164 165<div id="toc_left"> 166 167<p class="toc_h1"><a href="#6_developer_tools_and_options_compatibility">6. Developer Tools and Options Compatibility</a></p> 168 169<p class="toc_h2"><a href="#6_1_developer_tools">6.1. Developer Tools</a></p> 170 171<p class="toc_h2"><a href="#6_2_developer_options">6.2. Developer Options</a></p> 172 173<p class="toc_h1"><a href="#7_hardware_compatibility">7. Hardware Compatibility</a></p> 174 175<p class="toc_h2"><a href="#7_1_display_and_graphics">7.1. Display and Graphics</a></p> 176 177<p class="toc_h3"><a href="#7_1_1_screen_configuration">7.1.1. Screen Configuration</a></p> 178 179<p class="toc_h4"><a href="#7_1_1_1_screen_size">7.1.1.1. Screen Size</a></p> 180 181<p class="toc_h4"><a href="#7_1_1_2_screen_aspect_ratio">7.1.1.2. Screen Aspect Ratio</a></p> 182 183<p class="toc_h4"><a href="#7_1_1_3_screen_density">7.1.1.3. Screen Density</a></p> 184 185<p class="toc_h3"><a href="#7_1_2_display_metrics">7.1.2. Display Metrics</a></p> 186 187<p class="toc_h3"><a href="#7_1_3_screen_orientation">7.1.3. Screen Orientation</a></p> 188 189<p class="toc_h3"><a href="#7_1_4_2d_and_3d_graphics_acceleration">7.1.4. 2D and 3D Graphics Acceleration</a></p> 190 191<p class="toc_h3"><a href="#7_1_5_legacy_application_compatibility_mode">7.1.5. Legacy Application Compatibility Mode</a></p> 192 193<p class="toc_h3"><a href="#7_1_6_screen_technology">7.1.6. Screen Technology</a></p> 194 195<p class="toc_h3"><a href="#7_1_7_external_displays">7.1.7. Secondary Displays</a></p> 196 197<p class="toc_h2"><a href="#7_2_input_devices">7.2. Input Devices</a></p> 198 199<p class="toc_h3"><a href="#7_2_1_keyboard">7.2.1. Keyboard</a></p> 200 201<p class="toc_h3"><a href="#7_2_2_non-touch_navigation">7.2.2. Non-touch Navigation</a></p> 202 203<p class="toc_h3"><a href="#7_2_3_navigation_keys">7.2.3. Navigation Keys</a></p> 204 205<p class="toc_h3"><a href="#7_2_4_touchscreen_input">7.2.4. Touchscreen Input</a></p> 206 207<p class="toc_h3"><a href="#7_2_5_fake_touch_input">7.2.5. Fake Touch Input</a></p> 208 209<p class="toc_h3"><a href="#7_2_6_game_controller_support">7.2.6. Game Controller Support</a></p> 210 211<p class="toc_h4"><a href="#7_2_6_1_button_mapping">7.2.6.1. Button Mappings</a></p> 212 213<p class="toc_h3"><a href="#7_2_7_remote_control">7.2.7. Remote Control</a></p> 214 215<p class="toc_h2"><a href="#7_3_sensors">7.3. Sensors</a></p> 216 217<p class="toc_h3"><a href="#7_3_1_accelerometer">7.3.1. Accelerometer</a></p> 218 219<p class="toc_h3"><a href="#7_3_2_magnetometer">7.3.2. Magnetometer</a></p> 220 221<p class="toc_h3"><a href="#7_3_3_gps">7.3.3. GPS</a></p> 222 223</div> 224 225<div id="toc_right"> 226 227<p class="toc_h3"><a href="#7_3_4_gyroscope">7.3.4. Gyroscope</a></p> 228 229<p class="toc_h3"><a href="#7_3_5_barometer">7.3.5. Barometer</a></p> 230 231<p class="toc_h3"><a href="#7_3_6_thermometer">7.3.6. Thermometer</a></p> 232 233<p class="toc_h3"><a href="#7_3_7_photometer">7.3.7. Photometer</a></p> 234 235<p class="toc_h3"><a href="#7_3_8_proximity_sensor">7.3.8. Proximity Sensor</a></p> 236 237<p class="toc_h3"><a href="#7_3_9_hifi_sensors">7.3.9. High Fidelity Sensors</a></p> 238 239<p class="toc_h3"><a href="#7_3_10_fingerprint">7.3.10. Fingerprint Sensor</a></p> 240 241<p class="toc_h2"><a href="#7_4_data_connectivity">7.4. Data Connectivity</a></p> 242 243<p class="toc_h3"><a href="#7_4_1_telephony">7.4.1. Telephony</a></p> 244 245<p class="toc_h3"><a href="#7_4_2_ieee_80211_wi-fi">7.4.2. IEEE 802.11 (Wi-Fi)</a></p> 246 247<p class="toc_h4"><a href="#7_4_2_1_wi-fi_direct">7.4.2.1. Wi-Fi Direct</a></p> 248 249<p class="toc_h4"><a href="#7_4_2_2_wi-fi-tunneled-direct-link-setup">7.4.2.2. Wi-Fi Tunneled Direct Link Setup</a></p> 250 251<p class="toc_h3"><a href="#7_4_3_bluetooth">7.4.3. Bluetooth</a></p> 252 253<p class="toc_h3"><a href="#7_4_4_near-field_communications">7.4.4. Near-Field Communications</a></p> 254 255<p class="toc_h3"><a href="#7_4_5_minimum_network_capability">7.4.5. Minimum Network Capability</a></p> 256 257<p class="toc_h3"><a href="#7_4_6_sync_settings">7.4.6. Sync Settings</a></p> 258 259<p class="toc_h2"><a href="#7_5_cameras">7.5. Cameras</a></p> 260 261<p class="toc_h3"><a href="#7_5_1_rear-facing_camera">7.5.1. Rear-Facing Camera</a></p> 262 263<p class="toc_h3"><a href="#7_5_2_front-facing_camera">7.5.2. Front-Facing Camera</a></p> 264 265<p class="toc_h3"><a href="#7_5_3_external_camera">7.5.3. External Camera</a></p> 266 267<p class="toc_h3"><a href="#7_5_4_camera_api_behavior">7.5.4. Camera API Behavior</a></p> 268 269<p class="toc_h3"><a href="#7_5_5_camera_orientation">7.5.5. Camera Orientation</a></p> 270 271<p class="toc_h2"><a href="#7_6_memory_and_storage">7.6. Memory and Storage</a></p> 272 273<p class="toc_h3"><a href="#7_6_1_minimum_memory_and_storage">7.6.1. Minimum Memory and Storage</a></p> 274 275<p class="toc_h3"><a href="#7_6_2_application_shared_storage">7.6.2. Application Shared Storage</a></p> 276 277<p class="toc_h3"><a href="#7_6_3_adoptable_storage">7.6.3. Adoptable Storage</a></p> 278 279<p class="toc_h2"><a href="#7_7_usb">7.7. USB</a></p> 280 281<p class="toc_h2"><a href="#7_8_audio">7.8. Audio</a></p> 282 283<p class="toc_h3"><a href="#7_8_1_microphone">7.8.1. Microphone</a></p> 284 285<p class="toc_h3"><a href="#7_8_2_audio_output">7.8.2. Audio Output</a></p> 286 287<p class="toc_h4"><a href="#7_8_2_1_analog_audio_ports">7.8.2.1. Analog Audio Ports</a></p> 288 289<p class="toc_h3"><a href="#7_8_3_near_ultrasound">7.8.3. Near-Ultrasound</a></p> 290 291<p class="toc_h1"><a href="#8_performance_power">8. Performance and Power</a></p> 292 293<p class="toc_h2"><a href="#8_1_user_experience_consistency">8.1. User Experience Consistency</a></p> 294 295<p class="toc_h2"><a href="#8_2_file_i_o_access_performance">8.2. File I/O Access Performance</a></p> 296 297<p class="toc_h2"><a href="#8_3_power_saving_modes">8.3. Power-Saving Modes</a></p> 298 299<p class="toc_h2"><a href="#8_4_power_consumption_accounting">8.4. Power Consumption Accounting</a></p> 300 301</div> 302 303<div style="clear: both; page-break-after:always; height:1px"></div> 304 305<div id="toc_left"> 306 307<p class="toc_h1"><a href="#9_security_model_compatibility">9. Security Model Compatibility</a></p> 308 309<p class="toc_h2"><a href="#9_1_permissions">9.1. Permissions</a></p> 310 311<p class="toc_h2"><a href="#9_2_uid_and_process_isolation">9.2. UID and Process Isolation</a></p> 312 313<p class="toc_h2"><a href="#9_3_filesystem_permissions">9.3. Filesystem Permissions</a></p> 314 315<p class="toc_h2"><a href="#9_4_alternate_execution_environments">9.4. Alternate Execution Environments</a></p> 316 317<p class="toc_h2"><a href="#9_5_multi-user_support">9.5. Multi-User Support</a></p> 318 319<p class="toc_h2"><a href="#9_6_premium_sms_warning">9.6. Premium SMS Warning</a></p> 320 321<p class="toc_h2"><a href="#9_7_kernel_security_features">9.7. Kernel Security Features</a></p> 322 323<p class="toc_h2"><a href="#9_8_privacy">9.8. Privacy</a></p> 324 325<p class="toc_h2"><a href="#9_9_full-disk-encryption">9.9. Full-Disk Encryption</a></p> 326 327<p class="toc_h2"><a href="#9_10_verified_boot">9.10. Verified Boot</a></p> 328 329<p class="toc_h2"><a href="#9_11_keys_and_credentials">9.11. Keys and Credentials</a></p> 330 331<p class="toc_h2"><a href="#9_12_data_deletion">9.12. Data Deletion</a></p> 332 333<p class="toc_h1"><a href="#10_software_compatibility_testing">10. Software Compatibility Testing</a></p> 334 335<p class="toc_h2"><a href="#10_1_compatibility_test_suite">10.1. Compatibility Test Suite</a></p> 336 337<p class="toc_h2"><a href="#10_2_cts_verifier">10.2. CTS Verifier</a></p> 338 339<p class="toc_h1"><a href="#11_updatable_software">11. Updatable Software</a></p> 340 341<p class="toc_h1"><a href="#12_document_changelog">12. Document Changelog</a></p> 342 343<p class="toc_h1"><a href="#13_contact_us">13. Contact Us</a></p> 344 345</div> 346 347</div> 348 349<div style="clear: both"></div> 350 351<div id="main"> 352 353<h1 id="1_introduction">1. Introduction</h1> 354 355 356<p>This document enumerates the requirements that must be met in order for 357devices to be compatible with Android ANDROID_VERSION.</p> 358 359<p>The use of “MUST”, “MUST NOT”, 360“REQUIRED”, “SHALL”, “SHALL NOT”, 361“SHOULD”, “SHOULD NOT”, “RECOMMENDED”, 362“MAY”, and “OPTIONAL” is per the IETF standard 363defined in <a href="http://www.ietf.org/rfc/rfc2119.txt">RFC2119</a>.</p> 364 365<p>As used in this document, a “device implementer” or 366“implementer” is a person or organization developing a 367hardware/software solution running Android ANDROID_VERSION. A “device 368implementation” or “implementation is the hardware/software solution 369so developed.</p> 370 371<p>To be considered compatible with Android ANDROID_VERSION, device 372implementations MUST meet the requirements presented in this Compatibility 373Definition, including any documents incorporated via reference.</p> 374 375<p>Where this definition or the software tests described in 376<a href="#10_software_compatibility_testing">section 10</a> is silent, 377ambiguous, or incomplete, it is the responsibility of the device 378implementer to ensure compatibility with existing implementations.</p> 379 380<p>For this reason, the <a href="http://source.android.com/">Android Open Source 381Project</a> is both the reference and preferred implementation of Android. 382Device implementers are STRONGLY RECOMMENDED to base their implementations to 383the greatest extent possible on the “upstream” source code available 384from the Android Open Source Project. While some components can hypothetically 385be replaced with alternate implementations, it is STRONGLY RECOMMENDED to not 386follow this practice, as passing the software tests will become substantially 387more difficult. It is the implementer’s responsibility to ensure full 388behavioral compatibility with the standard Android implementation, including and 389beyond the Compatibility Test Suite. Finally, note that certain component 390substitutions and modifications are explicitly forbidden by this document.</p> 391 392<p>Many of the resources linked to in this document are derived directly or 393indirectly from the Android SDK and will be functionally identical to the 394information in that SDK’s documentation. In any cases where this 395Compatibility Definition or the Compatibility Test Suite disagrees with the 396SDK documentation, the SDK documentation is considered authoritative. Any 397technical details provided in the linked resources throughout this document are 398considered by inclusion to be part of this Compatibility Definition.</p> 399 400<h1 id="2_device_types">2. Device Types</h1> 401 402 403<p>While the Android Open Source Project has been used in the implementation of 404a variety of device types and form factors, many aspects of the architecture and 405compatibility requirements were optimized for handheld devices. Starting from 406Android 5.0, the Android Open Source Project aims to embrace a wider variety of 407device types as described in this section.</p> 408 409<p><strong>Android Handheld device</strong> refers to an Android device 410implementation that is typically used by holding it in the hand, such as mp3 411players, phones, and tablets. Android Handheld device implementations:</p> 412 413<ul> 414 <li>MUST have a touchscreen embedded in the device.</li> 415 <li>MUST have a power source that provides mobility, such as a battery.</li> 416</ul> 417 418<p><strong>Android Television device</strong> refers to an Android device 419implementation that is an entertainment interface for consuming digital media, 420movies, games, apps, and/or live TV for users sitting about ten feet away (a 421“lean back” or “10-foot user interface”). Android 422Television devices:</p> 423 424<ul> 425 <li>MUST have an embedded screen OR include a video output port, such as VGA, 426 HDMI, or a wireless port for display.</li> 427 <li>MUST declare the features 428 <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html#FEATURE_LEANBACK">android.software.leanback</a> 429 and android.hardware.type.television.</li> 430</ul> 431 432<p><strong>Android Watch device</strong> refers to an Android device 433implementation intended to be worn on the body, perhaps on the wrist, and:</p> 434 435<ul> 436 <li>MUST have a screen with the physical diagonal length in the range from 437 1.1 to 2.5 inches.</li> 438 <li>MUST declare the feature android.hardware.type.watch.</li> 439 <li>MUST support uiMode = 440 <a href="http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_WATCH">UI_MODE_TYPE_WATCH</a>. 441 </li> 442</ul> 443 444<p><strong>Android Automotive implementation</strong> refers to a vehicle head 445unit running Android as an operating system for part or all of the system and/or 446infotainment functionality. Android Automotive implementations:</p> 447 448<ul> 449 <li>MUST declare the feature android.hardware.type.automotive.</li> 450 <li>MUST support uiMode = 451 <a href="http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_CAR">UI_MODE_TYPE_CAR</a>. 452 </li> 453</ul> 454 455<p>All Android device implementations that do not fit into any of the above 456device types still MUST meet all requirements in this document to be Android 457ANDROID_VERSION compatible, unless the requirement is explicitly described to be 458only applicable to a specific Android device type from above.</p> 459 460<h2 id="2_1_device_configurations">2.1 Device Configurations</h2> 461 462 463<p>This is a summary of major differences in hardware configuration by device 464type. (Empty cells denote a “MAY”). Not all configurations are 465covered in this table; see relevant hardware sections for more detail.</p> 466<table> 467 <tr> 468 <th>Category</th> 469 <th>Feature</th> 470 <th>Section</th> 471 <th>Handheld</th> 472 <th>Television</th> 473 <th>Watch</th> 474 <th>Automotive</th> 475 <th>Other</th> 476 </tr> 477 <tr> 478 <td rowspan="3">Input</td> 479 <td>D-pad</td> 480 <td><a href="#7_2_2_non-touch-navigation">7.2.2. Non-touch Navigation</a></td> 481 <td></td> 482 <td>MUST</td> 483 <td></td> 484 <td></td> 485 <td></td> 486 </tr> 487 <tr> 488 <td>Touchscreen </td> 489 <td><a href="#7_2_4_touchscreen_input">7.2.4. Touchscreen input</a></td> 490 <td>MUST</td> 491 <td></td> 492 <td>MUST</td> 493 <td></td> 494 <td>SHOULD</td> 495 </tr> 496 <tr> 497 <td>Microphone </td> 498 <td><a href="#7_8_1_microphone">7.8.1. Microphone</a></td> 499 <td>MUST</td> 500 <td>SHOULD </td> 501 <td>MUST</td> 502 <td>MUST</td> 503 <td>SHOULD</td> 504 </tr> 505 <tr> 506 <td rowspan="2">Sensors</td> 507 <td>Accelerometer </td> 508 <td><a href="#7_3_1_accelerometer">7.3.1 Accelerometer</a></td> 509 <td>SHOULD</td> 510 <td></td> 511 <td>SHOULD</td> 512 <td></td> 513 <td>SHOULD</td> 514 </tr> 515 <tr> 516 <td>GPS</td> 517 <td><a href="#7_3_3_gps">7.3.3. GPS</a></td> 518 <td>SHOULD</td> 519 <td></td> 520 <td></td> 521 <td>SHOULD</td> 522 <td></td> 523 </tr> 524 <tr> 525 <td rowspan="5">Connectivity</td> 526 <td>Wi-Fi</td> 527 <td><a href="#7_4_2_ieee_802.11">7.4.2. IEEE 802.11</a></td> 528 <td>SHOULD</td> 529 <td> MUST</td> 530 <td></td> 531 <td>SHOULD</td> 532 <td>SHOULD</td> 533 </tr> 534 <tr> 535 <td>Wi-Fi Direct</td> 536 <td><a href="#7_4_2_1_wi-fi-direct">7.4.2.1. Wi-Fi Direct</a></td> 537 <td>SHOULD</td> 538 <td>SHOULD</td> 539 <td></td> 540 <td></td> 541 <td>SHOULD</td> 542 </tr> 543 <tr> 544 <td>Bluetooth</td> 545 <td><a href="#7_4_3_bluetooth">7.4.3. Bluetooth</a></td> 546 <td>SHOULD</td> 547 <td>MUST</td> 548 <td>MUST</td> 549 <td>MUST</td> 550 <td>SHOULD</td> 551 </tr> 552 <tr> 553 <td>Bluetooth Low Energy</td> 554 <td><a href="#7_4_3_bluetooth">7.4.3. Bluetooth</a></td> 555 <td>SHOULD</td> 556 <td>MUST</td> 557 <td>SHOULD</td> 558 <td>SHOULD</td> 559 <td>SHOULD</td> 560 </tr> 561 <tr> 562 <td>USB peripheral/host mode</td> 563 <td><a href="#7_7_usb">7.7. USB</a></td> 564 <td>SHOULD</td> 565 <td></td> 566 <td></td> 567 <td>SHOULD</td> 568 <td>SHOULD</td> 569 </tr> 570 <tr> 571 <td>Output</td> 572 <td>Speaker and/or Audio output ports</td> 573 <td><a href="#7_8_2_audio_output">7.8.2. Audio Output</a></td> 574 <td>MUST</td> 575 <td>MUST</td> 576 <td></td> 577 <td>MUST</td> 578 <td>MUST</td> 579 </tr> 580</table> 581 582 583<h1 id="3_software">3. Software</h1> 584 585 586<h2 id="3_1_managed_api_compatibility">3.1. Managed API Compatibility</h2> 587 588 589<p>The managed Dalvik bytecode execution environment is the primary vehicle for 590Android applications. The Android application programming interface (API) is 591the set of Android platform interfaces exposed to applications running in the 592managed runtime environment. Device implementations MUST provide complete 593implementations, including all documented behaviors, of any documented API 594exposed by the 595<a href="http://developer.android.com/reference/packages.html">Android SDK</a> 596or any API decorated with the “@SystemApi” marker in the upstream 597Android source code.</p> 598 599<p>Device implementations MUST NOT omit any managed APIs, alter API interfaces 600or signatures, deviate from the documented behavior, or include no-ops, except 601where specifically allowed by this Compatibility Definition.</p> 602 603<p>This Compatibility Definition permits some types of hardware for which 604Android includes APIs to be omitted by device implementations. In such cases, 605the APIs MUST still be present and behave in a reasonable way. See 606<a href="#7_hardware_compatibility">section 7</a> for specific requirements for 607this scenario.</p> 608 609<h2 id="3_2_soft_api_compatibility">3.2. Soft API Compatibility</h2> 610 611 612<p>In addition to the managed APIs from 613<a href="#3_1_managed_api_compatibility">section 3.1</a>, Android also includes 614a significant runtime-only “soft” API, in the form of such things as 615intents, permissions, and similar aspects of Android applications that cannot be 616enforced at application compile time.</p> 617 618<h3 id="3_2_1_permissions">3.2.1. Permissions</h3> 619 620 621<p>Device implementers MUST support and enforce all permission constants as 622documented by the 623<a href="http://developer.android.com/reference/android/Manifest.permission.html">Permission 624reference page</a>. Note that <a href="#9_security_model_compatibility">section 6259</a> lists additional requirements related to the Android security model.</p> 626 627<h3 id="3_2_2_build_parameters">3.2.2. Build Parameters</h3> 628 629 630<p>The Android APIs include a number of constants on the 631<a href="http://developer.android.com/reference/android/os/Build.html">android.os.Build 632class</a> that are intended to describe the current device. To provide 633consistent, meaningful values across device implementations, the table below 634includes additional restrictions on the formats of these values to which device 635implementations MUST conform.</p> 636<table> 637 <tr> 638 <th>Parameter</th> 639 <th>Details</th> 640 </tr> 641 <tr> 642 <td>VERSION.RELEASE</td> 643 <td>The version of the currently-executing Android system, in human-readable 644 format. This field MUST have one of the string values defined in 645 <a href="http://source.android.com/compatibility/ANDROID_VERSION/versions.html">ANDROID_VERSION</a>.</td> 646 </tr> 647 <tr> 648 <td>VERSION.SDK</td> 649 <td>The version of the currently-executing Android system, in a format 650 accessible to third-party application code. For Android ANDROID_VERSION, 651 this field MUST have the integer value ANDROID_VERSION_INT.</td> 652 </tr> 653 <tr> 654 <td>VERSION.SDK_INT</td> 655 <td>The version of the currently-executing Android system, in a format 656 accessible to third-party application code. For Android ANDROID_VERSION, 657 this field MUST have the integer value ANDROID_VERSION_INT.</td> 658 </tr> 659 <tr> 660 <td>VERSION.INCREMENTAL</td> 661 <td>A value chosen by the device implementer designating the specific build 662 of the currently-executing Android system, in human-readable format. This 663 value MUST NOT be reused for different builds made available to end users. A 664 typical use of this field is to indicate which build number or 665 source-control change identifier was used to generate the build. There are 666 no requirements on the specific format of this field, except that it MUST 667 NOT be null or the empty string ("").</td> 668 </tr> 669 <tr> 670 <td>BOARD</td> 671 <td>A value chosen by the device implementer identifying the specific 672 internal hardware used by the device, in human-readable format. A possible 673 use of this field is to indicate the specific revision of the board powering 674 the device. The value of this field MUST be encodable as 7-bit ASCII and 675 match the regular expression “^[a-zA-Z0-9_-]+$”.</td> 676 </tr> 677 <tr> 678 <td>BRAND</td> 679 <td>A value reflecting the brand name associated with the device as known to 680 the end users. MUST be in human-readable format and SHOULD represent the 681 manufacturer of the device or the company brand under which the device is 682 marketed. The value of this field MUST be encodable as 7-bit ASCII and match 683 the regular expression “^[a-zA-Z0-9_-]+$”.</td> 684 </tr> 685 <tr> 686 <td>SUPPORTED_ABIS</td> 687 <td>The name of the instruction set (CPU type + ABI convention) of native 688 code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API 689 Compatibility</a>.</td> 690 </tr> 691 <tr> 692 <td>SUPPORTED_32_BIT_ABIS</td> 693 <td>The name of the instruction set (CPU type + ABI convention) of native 694 code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API 695 Compatibility</a>.</td> 696 </tr> 697 <tr> 698 <td>SUPPORTED_64_BIT_ABIS</td> 699 <td>The name of the second instruction set (CPU type + ABI convention) of 700 native code. See <a href="#3_3_native_api_compatibility">section 3.3. Native 701 API Compatibility</a>.</td> 702 </tr> 703 <tr> 704 <td>CPU_ABI</td> 705 <td>The name of the instruction set (CPU type + ABI convention) of native 706 code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API 707 Compatibility</a>.</td> 708 </tr> 709 <tr> 710 <td>CPU_ABI2</td> 711 <td>The name of the second instruction set (CPU type + ABI convention) of 712 native code. See <a href="#3_3_native_api_compatibility">section 3.3. Native 713 API Compatibility</a>.</td> 714 </tr> 715 <tr> 716 <td>DEVICE</td> 717 <td>A value chosen by the device implementer containing the development name 718 or code name identifying the configuration of the hardware features and 719 industrial design of the device. The value of this field MUST be encodable 720 as 7-bit ASCII and match the regular expression 721 “^[a-zA-Z0-9_-]+$”.</td> 722 </tr> 723 <tr> 724 <td>FINGERPRINT</td> 725 <td>A string that uniquely identifies this build. It SHOULD be reasonably 726 human-readable. It MUST follow this template: 727 <p class="small">$(BRAND)/$(PRODUCT)/<br> 728 $(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</p> 729 <p>For example:</p> 730 <p class="small">acme/myproduct/<br> 731 mydevice:ANDROID_VERSION/LMYXX/3359:userdebug/test-keys</p> 732 <p>The fingerprint MUST NOT include whitespace characters. If other fields 733 included in the template above have whitespace characters, they MUST be 734 replaced in the build fingerprint with another character, such as the 735 underscore ("_") character. The value of this field MUST be encodable as 736 7-bit ASCII.</p></td> 737 </tr> 738 <tr> 739 <td>HARDWARE</td> 740 <td>The name of the hardware (from the kernel command line or /proc). It 741 SHOULD be reasonably human-readable. The value of this field MUST be 742 encodable as 7-bit ASCII and match the regular expression 743 “^[a-zA-Z0-9_-]+$”.</td> 744 </tr> 745 <tr> 746 <td>HOST</td> 747 <td>A string that uniquely identifies the host the build was built on, in 748 human-readable format. There are no requirements on the specific format of 749 this field, except that it MUST NOT be null or the empty string ("").</td> 750 </tr> 751 <tr> 752 <td>ID</td> 753 <td>An identifier chosen by the device implementer to refer to a specific 754 release, in human-readable format. This field can be the same as 755 android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently 756 meaningful for end users to distinguish between software builds. The value 757 of this field MUST be encodable as 7-bit ASCII and match the regular 758 expression “^[a-zA-Z0-9._-]+$”.</td> 759 </tr> 760 <tr> 761 <td>MANUFACTURER</td> 762 <td>The trade name of the Original Equipment Manufacturer (OEM) of the 763 product. There are no requirements on the specific format of this field, 764 except that it MUST NOT be null or the empty string ("").</td> 765 </tr> 766 <tr> 767 <td>MODEL</td> 768 <td>A value chosen by the device implementer containing the name of the 769 device as known to the end user. This SHOULD be the same name under which 770 the device is marketed and sold to end users. There are no requirements on 771 the specific format of this field, except that it MUST NOT be null or the 772 empty string ("").</td> 773 </tr> 774 <tr> 775 <td>PRODUCT</td> 776 <td>A value chosen by the device implementer containing the development name 777 or code name of the specific product (SKU) that MUST be unique within the 778 same brand. MUST be human-readable, but is not necessarily intended for view 779 by end users. The value of this field MUST be encodable as 7-bit ASCII and 780 match the regular expression “^[a-zA-Z0-9_-]+$”.</td> 781 </tr> 782 <tr> 783 <td>SERIAL</td> 784 <td>A hardware serial number, which MUST be available and unique across 785 devices with the same MODEL and MANUFACTURER. The value of this field MUST 786 be encodable as 7-bit ASCII and match the regular expression 787 “^([a-zA-Z0-9]{6,20})$”.</td> 788 </tr> 789 <tr> 790 <td>TAGS</td> 791 <td>A comma-separated list of tags chosen by the device implementer that 792 further distinguishes the build. This field MUST have one of the values 793 corresponding to the three typical Android platform signing configurations: 794 release-keys, dev-keys, test-keys.</td> 795 </tr> 796 <tr> 797 <td>TIME</td> 798 <td>A value representing the timestamp of when the build occurred.</td> 799 </tr> 800 <tr> 801 <td>TYPE</td> 802 <td>A value chosen by the device implementer specifying the runtime 803 configuration of the build. This field MUST have one of the values 804 corresponding to the three typical Android runtime configurations: user, 805 userdebug, or eng.</td> 806 </tr> 807 <tr> 808 <td>USER</td> 809 <td>A name or user ID of the user (or automated user) that generated the 810 build. There are no requirements on the specific format of this field, 811 except that it MUST NOT be null or the empty string ("").</td> 812 </tr> 813 <tr> 814 <td>SECURITY_PATCH</td> 815 <td>An value indicating the security patch level of a build. It MUST signify 816 that the build includes all security patches issued up through the 817 designated Android Public Security Bulletin. It MUST be in the format 818 [YYYY-MM-DD], matching the Public Security Bulletin's broadcast date, for 819 example [2015-10-01].</td> 820 </tr> 821 <tr> 822 <td>BASE_OS</td> 823 <td>An value representing the FINGERPRINT parameter of the build that is 824 otherwise identical to this build except for the patches provided in the 825 Android Public Security Bulletin. It MUST report the correct value and if 826 such a build does not exist, report an empty string ("").</td> 827 </tr> 828</table> 829 830 831<h3 id="3_2_3_intent_compatibility">3.2.3. Intent Compatibility</h3> 832 833 834<p>Device implementations MUST honor Android’s loose-coupling intent 835system, as described in the sections below. By “honored” it is meant 836that the device implementer MUST provide an Android Activity or Service that 837specifies amatching intent filter that binds to and implements correct behavior 838for each specified intent pattern.</p> 839 840<h4 id="3_2_3_1_core_application_intents">3.2.3.1. Core Application Intents</h4> 841 842 843<p>Android intents allow application components to request functionality from 844other Android components. The Android upstream project includes a list of 845applications considered core Android applications, which implements several 846intent patterns to perform common actions. The core Android applications are: 847</p> 848 849<ul> 850 <li>Desk Clock</li> 851 <li>Browser</li> 852 <li>Calendar</li> 853 <li>Contacts</li> 854 <li>Gallery</li> 855 <li>GlobalSearch</li> 856 <li>Launcher</li> 857 <li>Music</li> 858 <li>Settings</li> 859</ul> 860 861<p>Device implementations SHOULD include the core Android applications as 862appropriate but MUST include a component implementing the same intent patterns 863defined by all the “public” Activity or Service components of these 864core Android applications. Note that Activity or Service components are 865considered “public” when the attribute android:exported is absent or 866has the value true.</p> 867 868<h4 id="3_2_3_2_intent_resolution">3.2.3.2. Intent Resolution</h4> 869 870 871<p>As Android is an extensible platform, device implementations MUST allow each 872intent pattern referenced in <a href="#3_2_3_1_core_application_intents">section 8733.2.3.1</a> to be overridden by third-party applications. The upstream Android 874open source implementation allows this by default; device implementers MUST NOT 875attach special privileges to system applications' use of these intent patterns, 876or prevent third-party applications from binding to and assuming control of 877these patterns. This prohibition specifically includes but is not limited to 878disabling the “Chooser” user interface that allows the user to 879select between multiple applications that all handle the same intent pattern. 880</p> 881 882<p>Device implementations MUST provide a user interface for users to modify the 883default activity for intents.</p> 884 885<p>However, device implementations MAY provide default activities for specific 886URI patterns (e.g. http://play.google.com) when the default activity provides a 887more specific attribute for the data URI. For example, an intent filter pattern 888specifying the data URI “http://www.android.com” is more specific 889than the browser's core intent pattern for “http://”.</p> 890 891<p>Android also includes a mechanism for third-party apps to declare an 892authoritative default 893<a href="https://developer.android.com/training/app-links">app linking 894behavior</a> for certain types of web URI intents. When such authoritative 895declarations are defined in an app's intent filter patterns, device 896implementations:</p> 897 898<ul> 899 <li>MUST attempt to validate any intent filters by performing the validation 900 steps defined in the 901 <a href="https://developers.google.com/digital-asset-links">Digital Asset 902 Links specification</a> as implemented by the Package Manager in the upstream 903 Android Open Source Project.</li> 904 <li>MUST attempt validation of the intent filters during the installation of 905 the application and set all successfully validated UIR intent filters as 906 default app handlers for their UIRs.</li> 907 <li>MAY set specific URI intent filters as default app handlers for their 908 URIs, if they are successfully verified but other candidate URI filters fail 909 verification. If a device implementation does this, it MUST provide the user 910 appropriate per-URI pattern overrides in the settings menu.</li> 911 <li>MUST provide the user with per-app App Links controls in Settings as 912 follows: 913 <ul> 914 <li>The user MUST be able to override holistically the default app links 915 behavior for an app to be: always open, always ask, or never open, which 916 must apply to all candidate URI intent filters equally.</li> 917 <li>The user MUST be able to see a list of the candidate URI intent filters. 918 </li> 919 <li>The device implementation MAY provide the user with the ability to 920 override specific candidate URI intent filters that were successfully 921 verified, on a per-intent filter basis.</li> 922 <li>The device implementation MUST provide users with the ability to view 923 and override specific candidate URI intent filters if the device 924 implementation lets some candidate URI intent filters succeed verification 925 while some others can fail.</li> 926 </ul> 927 </li> 928</ul> 929 930<h4 id="3_2_3_3_intent_namespaces">3.2.3.3. Intent Namespaces</h4> 931 932 933<p>Device implementations MUST NOT include any Android component that honors any 934new intent or broadcast intent patterns using an ACTION, CATEGORY, or other key 935string in the android.* or com.android.* namespace. Device implementers MUST NOT 936include any Android components that honor any new intent or broadcast intent 937patterns using an ACTION, CATEGORY, or other key string in a package space 938belonging to another organization. Device implementers MUST NOT alter or extend 939any of the intent patterns used by the core apps listed in 940<a href="#3_2_3_1_core_application_intents">section 3.2.3.1</a>. Device 941implementations MAY include intent patterns using namespaces clearly and 942obviously associated with their own organization. This prohibition is analogous 943to that specified for Java language classes in 944<a href="#3_6_api_namespaces">section 3.6</a>.</p> 945 946<h4 id="3_2_3_4_broadcast_intents">3.2.3.4. Broadcast Intents</h4> 947 948 949<p>Third-party applications rely on the platform to broadcast certain intents to 950notify them of changes in the hardware or software environment. 951Android-compatible devices MUST broadcast the public broadcast intents in 952response to appropriate system events. Broadcast intents are described in the 953SDK documentation.</p> 954 955<h4 id="3_2_3_5_default_app_settings">3.2.3.5. Default App Settings</h4> 956 957 958<p>Android includes settings that provide users an easy way to select their 959default applications, for example for Home screen or SMS. Where it makes sense, 960device implementations MUST provide a similar settings menu and be compatible 961with the intent filter pattern and API methods described in the SDK 962documentation as below.</p> 963 964<p>Device implementations:</p> 965 966<ul> 967 <li>MUST honor the <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_HOME_SETTINGS">android.settings.HOME_SETTINGS</a> 968 intent to show a default app settings menu for Home Screen, if the device 969 implementation reports android.software.home_screen.</li> 970 <li>MUST provide a settings menu that will call the 971 <a href="http://developer.android.com/reference/android/provider/Telephony.Sms.Intents.html">android.provider.Telephony.ACTION_CHANGE_DEFAULT</a> 972 intent to show a dialog to change the default SMS application, if the device 973 implementation reports android.hardware.telephony.</li> 974 <li>MUST honor the <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFC_PAYMENT_SETTINGS">android.settings.NFC_PAYMENT_SETTINGS</a> 975 intent to show a default app settings menu for Tap and Pay, if the device 976 implementation reports android.hardware.nfc.hce.</li> 977</ul> 978 979<h2 id="3_3_native_api_compatibility">3.3. Native API Compatibility</h2> 980 981 982<h3 id="3_3_1_application_binary_interfaces">3.3.1. Application Binary Interfaces</h3> 983 984 985<p>Managed Dalvik bytecode can call into native code provided in the application 986.apk file as an ELF .so file compiled for the appropriate device hardware 987architecture. As native code is highly dependent on the underlying processor 988technology, Android defines a number of Application Binary Interfaces (ABIs) in 989the Android NDK. Device implementations MUST be compatible with one or more 990defined ABIs, and MUST implement compatibility with the Android NDK, as below.</p> 991 992<p>If a device implementation includes support for an Android ABI, it:</p> 993 994<ul> 995 <li>MUST include support for code running in the managed environment to call 996 into native code, using the standard Java Native Interface (JNI) semantics.</li> 997 <li>MUST be source-compatible (i.e. header compatible) and binary-compatible 998 (for the ABI) with each required library in the list below.</li> 999 <li>MUST support the equivalent 32-bit ABI if any 64-bit ABI is supported.</li> 1000 <li>MUST accurately report the native Application Binary Interface (ABI) 1001 supported by the device, via the android.os.Build.SUPPORTED_ABIS, 1002 android.os.Build.SUPPORTED_32_BIT_ABIS, and 1003 android.os.Build.SUPPORTED_64_BIT_ABIS parameters, each a comma separated list 1004 of ABIs ordered from the most to the least preferred one.</li> 1005 <li>MUST report, via the above parameters, only those ABIs documented and 1006 described in the latest version of the 1007 <a href="https://developer.android.com/ndk/guides/abis.html">Android NDK ABI 1008 Management documentation</a>, and MUST include support for the 1009 <a href="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/Beijfcja.html">Advanced 1010 SIMD</a> (a.k.a. NEON) extension.</li> 1011 <li>SHOULD be built using the source code and header files available in the 1012 upstream Android Open Source Project</li> 1013</ul> 1014 1015<p>The following native code APIs MUST be available to apps that include native 1016code:</p> 1017 1018<ul> 1019 <li>libc (C library)</li> 1020 <li>libm (math library)</li> 1021 <li>Minimal support for C++</li> 1022 <li>JNI interface</li> 1023 <li>liblog (Android logging)</li> 1024 <li>libz (Zlib compression)</li> 1025 <li>libdl (dynamic linker)</li> 1026 <li>libGLESv1_CM.so (OpenGL ES 1.x)</li> 1027 <li>libGLESv2.so (OpenGL ES 2.0)</li> 1028 <li>libGLESv3.so (OpenGL ES 3.x)</li> 1029 <li>libEGL.so (native OpenGL surface management)</li> 1030 <li>libjnigraphics.so</li> 1031 <li>libOpenSLES.so (OpenSL ES 1.0.1 audio support)</li> 1032 <li>libOpenMAXAL.so (OpenMAX AL 1.0.1 support)</li> 1033 <li>libandroid.so (native Android activity support)</li> 1034 <li>libmediandk.so (native media APIs support)</li> 1035 <li>Support for OpenGL, as described below</li> 1036</ul> 1037 1038<p>Note that future releases of the Android NDK may introduce support for 1039additional ABIs. If a device implementation is not compatible with an existing 1040predefined ABI, it MUST NOT report support for any ABIs at all.</p> 1041 1042<p>Note that device implementations MUST include libGLESv3.so and it MUST symlink 1043(symbolic link) to libGLESv2.so. in turn, MUST export all the OpenGL ES 3.1 and 1044<a href="http://developer.android.com/guide/topics/graphics/opengl.html#aep">Android 1045Extension Pack</a> function symbols as defined in the NDK release android-21. 1046Although all the symbols must be present, only the corresponding functions for 1047OpenGL ES versions and extensions actually supported by the device must be fully 1048implemented.</p> 1049 1050<p>Device implementations MUST NOT include a native library with the 1051name libvulkan.so.</p> 1052 1053<p>Native code compatibility is challenging. For this reason, device 1054implementers are <strong>STRONGLY RECOMMENDED</strong> to use the 1055implementations of the libraries listed above from the upstream Android Open 1056Source Project.</p> 1057 1058<h3 id="3_3_2_32-bit_arm_native_code_compatibility">3.3.2. 105932-bit ARM Native Code Compatibility</h3> 1060 1061<p>The ARMv8 architecture deprecates several CPU operations, including some 1062operations used in existing native code. On 64-bit ARM devices, the following 1063deprecated operations MUST remain available to 32-bit native ARM code, either 1064through native CPU support or through software emulation:</p> 1065 1066<ul> 1067 <li>SWP and SWPB instructions</li> 1068 <li>SETEND instruction</li> 1069 <li>CP15ISB, CP15DSB, and CP15DMB barrier operations</li> 1070</ul> 1071 1072<p>Legacy versions of the Android NDK used /proc/cpuinfo to discover CPU 1073features from 32-bit ARM native code. For compatibility with applications built 1074using this NDK, devices MUST include the following lines in /proc/cpuinfo when 1075it is read by 32-bit ARM applications:</p> 1076 1077<ul> 1078 <li>"Features: ", followed by a list of any optional ARMv7 CPU 1079 features supported by the device.</li> 1080 <li>"CPU architecture: ", followed by an integer describing the 1081 device's highest supported ARM architecture (e.g., "8" for ARMv8 1082 devices).</li> 1083</ul> 1084 1085<p>These requirements only apply when /proc/cpuinfo is read by 32-bit ARM 1086applications. Devices SHOULD not alter /proc/cpuinfo when read by 64-bit ARM or 1087non-ARM applications.</p> 1088 1089<h2 id="3_4_web_compatibility">3.4. Web Compatibility</h2> 1090 1091 1092<h3 id="3_4_1_webview_compatibility">3.4.1. WebView Compatibility</h3> 1093 1094<div class="note"> 1095<p>Android Watch devices MAY, but all other device implementations MUST provide 1096a complete implementation of the android.webkit.Webview API.</p> 1097</div> 1098 1099 1100<p>The platform feature android.software.webview MUST be reported on any device 1101that provides a complete implementation of the android.webkit.WebView API, and 1102MUST NOT be reported on devices without a complete implementation of the API. 1103The Android Open Source implementation uses code from the Chromium Project to 1104implement the 1105<a href="http://developer.android.com/reference/android/webkit/WebView.html">android.webkit.WebView</a>. 1106Because it is not feasible to develop a comprehensive test suite for a web 1107rendering system, device implementers MUST use the specific upstream build of 1108Chromium in the WebView implementation. Specifically:</p> 1109 1110<ul> 1111 <li>Device android.webkit.WebView implementations MUST be based on the 1112 <a href="http://www.chromium.org/">Chromium</a> build from the upstream 1113 Android Open Source Project for Android ANDROID_VERSION. This build includes 1114 a specific set of functionality and security fixes for the WebView.</li> 1115 <li>The user agent string reported by the WebView MUST be in this format: 1116 <p>Mozilla/5.0 (Linux; Android $(VERSION); $(MODEL) Build/$(BUILD); wv) 1117 AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 $(CHROMIUM_VER) Mobile 1118 Safari/537.36</p> 1119 <ul> 1120 <li>The value of the $(VERSION) string MUST be the same as the value for 1121 android.os.Build.VERSION.RELEASE.</li> 1122 <li>The value of the $(MODEL) string MUST be the same as the value for 1123 android.os.Build.MODEL.</li> 1124 <li>The value of the $(BUILD) string MUST be the same as the value for 1125 android.os.Build.ID.</li> 1126 <li>The value of the $(CHROMIUM_VER) string MUST be the version of Chromium 1127 in the upstream Android Open Source Project.</li> 1128 <li>Device implementations MAY omit Mobile in the user agent string.</li> 1129 </ul> 1130 </li> 1131</ul> 1132 1133<p>The WebView component SHOULD include support for as many HTML5 features as 1134possible and if it supports the feature SHOULD conform to the 1135<a href="http://html.spec.whatwg.org/multipage/">HTML5 specification</a>.</p> 1136 1137<h3 id="3_4_2_browser_compatibility">3.4.2. Browser Compatibility</h3> 1138 1139<div class="note"> 1140<p>Android Television, Watch, and Android Automotive implementations MAY omit a 1141browser application, but MUST support the public intent patterns as described in 1142<a href="#3_2_3_1_core_application_intents">section 3.2.3.1</a>. All other types 1143of device implementations MUST include a standalone Browser application for 1144general user web browsing.</p> 1145</div> 1146 1147<p>The standalone Browser MAY be based on a browser technology other than WebKit. 1148However, even if an alternate Browser application is used, the 1149android.webkit.WebView component provided to third-party applications MUST be 1150based on WebKit, as described in <a href="#3_4_1_webview_compatibility">section 11513.4.1</a>.</p> 1152 1153<p>Implementations MAY ship a custom user agent string in the standalone Browser 1154application.</p> 1155 1156<p>The standalone Browser application (whether based on the upstream WebKit 1157Browser application or a third-party replacement) SHOULD include support for as 1158much of <a href="http://html.spec.whatwg.org/multipage/">HTML5</a> as possible. 1159Minimally, device implementations MUST support each of these APIs associated 1160with HTML5:</p> 1161 1162<ul> 1163 <li><a href="http://www.w3.org/html/wg/drafts/html/master/browsers.html#offline">application 1164 cache/offline operation</a></li> 1165 <li><a href="http://www.w3.org/html/wg/drafts/html/master/semantics.html#video"><video> 1166 tag</a></li> 1167 <li><a href="http://www.w3.org/TR/geolocation-API/">geolocation</a></li> 1168</ul> 1169 1170<p>Additionally, device implementations MUST support the HTML5/W3C 1171<a href="http://www.w3.org/TR/webstorage/">webstorage API</a> and SHOULD support 1172the HTML5/W3C <a href="http://www.w3.org/TR/IndexedDB/">IndexedDB API</a>. Note 1173that as the web development standards bodies are transitioning to favor 1174IndexedDB over webstorage, IndexedDB is expected to become a required component 1175in a future version of Android.</p> 1176 1177<h2 id="3_5_api_behavioral_compatibility">3.5. API Behavioral Compatibility</h2> 1178 1179 1180<p>The behaviors of each of the API types (managed, soft, native, and web) must 1181be consistent with the preferred implementation of the upstream 1182<a href="http://source.android.com/">Android Open Source Project</a>. Some 1183specific areas of compatibility are:</p> 1184 1185<ul> 1186 <li>Devices MUST NOT change the behavior or semantics of a standard intent. 1187 </li> 1188 <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a 1189 particular type of system component (such as Service, Activity, 1190 ContentProvider, etc.).</li> 1191 <li>Devices MUST NOT change the semantics of a standard permission.</li> 1192</ul> 1193 1194<p>The above list is not comprehensive. The Compatibility Test Suite (CTS) tests 1195significant portions of the platform for behavioral compatibility, but not all. 1196It is the responsibility of the implementer to ensure behavioral compatibility 1197with the Android Open Source Project. For this reason, device implementers 1198SHOULD use the source code available via the Android Open Source Project where 1199possible, rather than re-implement significant parts of the system.</p> 1200 1201<h2 id="3_6_api_namespaces">3.6. API Namespaces</h2> 1202 1203 1204<p>Android follows the package and class namespace conventions defined by the 1205Java programming language. To ensure compatibility with third-party 1206applications, device implementers MUST NOT make any prohibited modifications 1207(see below) to these package namespaces:</p> 1208 1209<ul> 1210 <li>java.*</li> 1211 <li>javax.*</li> 1212 <li>sun.*</li> 1213 <li>android.*</li> 1214 <li>com.android.*</li> 1215</ul> 1216 1217<p><strong>Prohibited modifications include</strong>:</p> 1218 1219<ul> 1220 <li>Device implementations MUST NOT modify the publicly exposed APIs on the 1221 Android platform by changing any method or class signatures, or by removing 1222 classes or class fields.</li> 1223 <li>Device implementers MAY modify the underlying implementation of the APIs, 1224 but such modifications MUST NOT impact the stated behavior and Java-language 1225 signature of any publicly exposed APIs.</li> 1226 <li>Device implementers MUST NOT add any publicly exposed elements (such as 1227 classes or interfaces, or fields or methods to existing classes or interfaces) 1228 to the APIs above.</li> 1229</ul> 1230 1231<p>A “publicly exposed element” is any construct that is not 1232decorated with the“@hide” marker as used in the upstream Android 1233source code. In other words, device implementers MUST NOT expose new APIs or 1234alter existing APIs in the namespaces noted above. Device implementers MAY make 1235internal-only modifications, but those modifications MUST NOT be advertised or 1236otherwise exposed to developers.</p> 1237 1238<p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a 1239namespace owned by or referring to another organization. For instance, device 1240implementers MUST NOT add APIs to the com.google.* or similar namespace: only 1241Google may do so. Similarly, Google MUST NOT add APIs to other companies' 1242namespaces. Additionally, if a device implementation includes custom APIs 1243outside the standard Android namespace, those APIs MUST be packaged in an 1244Android shared library so that only apps that explicitly use them (via the 1245lt;uses-librarygt; mechanism) are affected by the increased memory usage of such 1246APIs.</p> 1247 1248<p>If a device implementer proposes to improve one of the package namespaces 1249above (such as by adding useful new functionality to an existing API, or adding 1250a new API), the implementer SHOULD visit 1251<a href="http://source.android.com/">source.android.com</a> and begin the 1252process for contributing changes and code, according to the information on that 1253site.</p> 1254 1255<p>Note that the restrictions above correspond to standard conventions for 1256naming APIs in the Java programming language; this section simply aims to 1257reinforce those conventions and make them binding through inclusion in this 1258Compatibility Definition.</p> 1259 1260<h2 id="3_7_runtime_compatibility">3.7. Runtime Compatibility</h2> 1261 1262 1263<p>Device implementations MUST support the full Dalvik Executable (DEX) format 1264and <a href="https://android.googlesource.com/platform/dalvik/">Dalvik bytecode 1265specification and semantics</a>. Device implementers SHOULD use ART, the 1266reference upstream implementation of the Dalvik Executable Format, and the 1267reference implementation’s package management system.</p> 1268 1269<p>Device implementations MUST configure Dalvik runtimes to allocate memory in 1270accordance with the upstream Android platform, and as specified by the 1271following table. (See <a href="#7_1_1_screen_configuration">section 7.1.1</a> 1272for screen size and screen density definitions.) Note that memory values 1273specified below are considered minimum values and device implementations MAY 1274allocate more memory per application.</p> 1275 1276<table> 1277 <tr> 1278 <th>Screen Layout</th> 1279 <th>Screen Density</th> 1280 <th>Minimum Application Memory</th> 1281 </tr> 1282 <tr> 1283 <td rowspan="12">Android Watch</td> 1284 <td>120 dpi (ldpi)</td> 1285 <td rowspan="3">32MB</td> 1286 </tr> 1287 <tr> 1288 <td>160 dpi (mdpi)</td> 1289 </tr> 1290 <tr> 1291 <td>213 dpi (tvdpi)</td> 1292 </tr> 1293 <tr> 1294 <td>240 dpi (hdpi)</td> 1295 <td rowspan="2">36MB</td> 1296 </tr> 1297 <tr> 1298 <td>280 dpi (280dpi)</td> 1299 </tr> 1300 <tr> 1301 <td>320 dpi (xhdpi)</td> 1302 <td rowspan="2">48MB</td> 1303 </tr> 1304 <tr> 1305 <td>360 dpi (360dpi)</td> 1306 </tr> 1307 <tr> 1308 <td>400 dpi (400dpi)</td> 1309 <td>56MB</td> 1310 </tr> 1311 <tr> 1312 <td>420 dpi (420dpi)</td> 1313 <td>64MB</td> 1314 </tr> 1315 <tr> 1316 <td>480 dpi (xxhdpi)</td> 1317 <td>88MB</td> 1318 </tr> 1319 <tr> 1320 <td>560 dpi (560dpi)</td> 1321 <td>112MB</td> 1322 </tr> 1323 <tr> 1324 <td>640 dpi (xxxhdpi)</td> 1325 <td>154MB</td> 1326 </tr> 1327 <tr> 1328 <td rowspan="12">small/normal</td> 1329 <td>120 dpi (ldpi)</td> 1330 <td rowspan="2">32MB</td> 1331 </tr> 1332 <tr> 1333 <td>160 dpi (mdpi)</td> 1334 </tr> 1335 <tr> 1336 <td>213 dpi (tvdpi)</td> 1337 <td rowspan="3">48MB</td> 1338 </tr> 1339 <tr> 1340 <td>240 dpi (hdpi)</td> 1341 </tr> 1342 <tr> 1343 <td>280 dpi (280dpi)</td> 1344 </tr> 1345 <tr> 1346 <td>320 dpi (xhdpi)</td> 1347 <td rowspan="2">80MB</td> 1348 </tr> 1349 <tr> 1350 <td>360 dpi (360dpi)</td> 1351 </tr> 1352 <tr> 1353 <td>400 dpi (400dpi)</td> 1354 <td>96MB</td> 1355 </tr> 1356 <tr> 1357 <td>420 dpi (420dpi)</td> 1358 <td>112MB</td> 1359 </tr> 1360 <tr> 1361 <td>480 dpi (xxhdpi)</td> 1362 <td>128MB</td> 1363 </tr> 1364 <tr> 1365 <td>560 dpi (560dpi)</td> 1366 <td>192MB</td> 1367 </tr> 1368 <tr> 1369 <td>640 dpi (xxxhdpi)</td> 1370 <td>256MB</td> 1371 </tr> 1372 <tr> 1373 <td rowspan="12">large</td> 1374 <td>120 dpi (ldpi)</td> 1375 <td>32MB</td> 1376 </tr> 1377 <tr> 1378 <td>160 dpi (mdpi)</td> 1379 <td>48MB</td> 1380 </tr> 1381 <tr> 1382 <td>213 dpi (tvdpi)</td> 1383 <td rowspan="2">80MB</td> 1384 </tr> 1385 <tr> 1386 <td>240 dpi (hdpi)</td> 1387 </tr> 1388 <tr> 1389 <td>280 dpi (280dpi)</td> 1390 <td>96MB</td> 1391 </tr> 1392 <tr> 1393 <td>320 dpi (xhdpi)</td> 1394 <td>128MB</td> 1395 </tr> 1396 <tr> 1397 <td>360 dpi (360dpi)</td> 1398 <td>160MB</td> 1399 </tr> 1400 <tr> 1401 <td>400 dpi (400dpi)</td> 1402 <td>192MB</td> 1403 </tr> 1404 <tr> 1405 <td>420 dpi (420dpi)</td> 1406 <td>228MB</td> 1407 </tr> 1408 <tr> 1409 <td>480 dpi (xxhdpi)</td> 1410 <td>256MB</td> 1411 </tr> 1412 <tr> 1413 <td>560 dpi (560dpi)</td> 1414 <td>384MB</td> 1415 </tr> 1416 <tr> 1417 <td>640 dpi (xxxhdpi)</td> 1418 <td>512MB</td> 1419 </tr> 1420 <tr> 1421 <td rowspan="12">xlarge</td> 1422 <td>120 dpi (ldpi)</td> 1423 <td>48MB</td> 1424 </tr> 1425 <tr> 1426 <td>160 dpi (mdpi)</td> 1427 <td>80MB</td> 1428 </tr> 1429 <tr> 1430 <td>213 dpi (tvdpi)</td> 1431 <td rowspan="2">96MB</td> 1432 </tr> 1433 <tr> 1434 <td>240 dpi (hdpi)</td> 1435 </tr> 1436 <tr> 1437 <td>280 dpi (280dpi)</td> 1438 <td>144MB</td> 1439 </tr> 1440 <tr> 1441 <td>320 dpi (xhdpi)</td> 1442 <td>192MB</td> 1443 </tr> 1444 <tr> 1445 <td>360 dpi (360dpi)</td> 1446 <td>240MB</td> 1447 </tr> 1448 <tr> 1449 <td>400 dpi (400dpi)</td> 1450 <td>288MB</td> 1451 </tr> 1452 <tr> 1453 <td>420 dpi (420dpi)</td> 1454 <td>336MB</td> 1455 </tr> 1456 <tr> 1457 <td>480 dpi (xxhdpi)</td> 1458 <td>384MB</td> 1459 </tr> 1460 <tr> 1461 <td>560 dpi (560dpi)</td> 1462 <td>576MB</td> 1463 </tr> 1464 <tr> 1465 <td>640 dpi (xxxhdpi)</td> 1466 <td>768MB</td> 1467 </tr> 1468</table> 1469 1470 1471<h2 id="3_8_user_interface_compatibility">3.8. User Interface Compatibility</h2> 1472 1473 1474<h3 id="3_8_1_launcher_home_screen">3.8.1. Launcher (Home Screen)</h3> 1475 1476 1477<p>Android includes a launcher application (home screen) and support for 1478third-party applications to replace the device launcher (home screen). Device 1479implementations that allow third-party applications to replace the device home 1480screen MUST declare the platform feature android.software.home_screen.</p> 1481 1482<h3 id="3_8_2_widgets">3.8.2. Widgets</h3> 1483 1484<div class="note"> 1485<p>Widgets are optional for all Android device implementations, but SHOULD be 1486supported on Android Handheld devices.</p> 1487</div> 1488 1489 1490<p>Android defines a component type and corresponding API and lifecycle that 1491allows applications to expose an 1492<a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">“AppWidget”</a> 1493to the end user, a feature that is STRONGLY RECOMMENDED to be supported on 1494Handheld Device implementations. Device implementations that support embedding 1495widgets on the home screen MUST meet the following requirements and declare 1496support for platform feature android.software.app_widgets.</p> 1497 1498<ul> 1499 <li>Device launchers MUST include built-in support for AppWidgets and expose 1500 user interface affordances to add, configure, view, and remove AppWidgets 1501 directly within the Launcher.</li> 1502 <li>Device implementations MUST be capable of rendering widgets that are 4 x 4 1503 in the standard grid size. See the 1504 <a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">App 1505 Widget Design Guidelines</a> in the Android SDK documentation for details. 1506 </li> 1507 <li>Device implementations that include support for lock screen MAY support 1508 application widgets on the lock screen.</li> 1509</ul> 1510 1511<h3 id="3_8_3_notifications">3.8.3. Notifications</h3> 1512 1513 1514<p>Android includes APIs that allow developers to 1515<a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">notify 1516users of notable events</a> using hardware and software features of the device.</p> 1517 1518<p>Some APIs allow applications to perform notifications or attract attention 1519using hardware—specifically sound, vibration, and light. Device 1520implementations MUST support notifications that use hardware features, as 1521described in the SDK documentation, and to the extent possible with the device 1522implementation hardware. For instance, if a device implementation includes a 1523vibrator, it MUST correctly implement the vibration APIs. If a device 1524implementation lacks hardware, the corresponding APIs MUST be implemented as 1525no-ops. This behavior is further detailed in 1526<a href="#7_hardware_compatibility">section 7</a>.</p> 1527 1528<p>Additionally, the implementation MUST correctly render all 1529<a href="https://developer.android.com/guide/topics/resources/available-resources.html">resources</a> 1530(icons, animation files etc.) provided for in the APIs, or in the Status/System 1531Bar <a href="http://developer.android.com/design/style/iconography.html">icon 1532style guide</a>, which in the case of an Android Television device includes the 1533possibility to not display the notifications. Device implementers MAY provide an 1534alternative user experience for notifications than that provided by the 1535reference Android Open Source implementation; however, such alternative 1536notification systems MUST support existing notification resources, as above.</p> 1537 1538<p>Android includes support for various notifications, such as:</p> 1539 1540<ul> 1541 <li><strong>Rich notifications</strong>. Interactive Views for ongoing 1542 notifications.</li> 1543 <li><strong>Heads-up notifications</strong>. Interactive Views users can act 1544 on or dismiss without leaving the current app.</li> 1545 <li><strong>Lockscreen notifications</strong>. Notifications shown over a lock 1546 screen with granular control on visibility.</li> 1547</ul> 1548 1549<p>Android device implementations, when such notifications are made visible, 1550MUST properly execute Rich and Heads-up notifications and include the 1551title/name, icon, text as 1552<a href="https://developer.android.com/design/patterns/notifications.html">documented 1553in the Android APIs</a>.</p> 1554 1555<p>Android includes Notification Listener Service APIs that allow apps (once 1556explicitly enabled by the user) to receive a copy of all notifications as they 1557are posted or updated. Device implementations MUST correctly and promptly send 1558notifications in their entirety to all such installed and user-enabled listener 1559services, including any and all metadata attached to the Notification object. 1560</p> 1561 1562<h3 id="3_8_4_search">3.8.4. Search</h3> 1563 1564 1565<p>Android includes APIs that allow developers to 1566<a href="http://developer.android.com/reference/android/app/SearchManager.html">incorporate 1567search</a> into their applications and expose their application’s data 1568into the global system search. Generally speaking, this functionality consists 1569of a single, system-wide user interface that allows users to enter queries, 1570displays suggestions as users type, and displays results. The Android APIs allow 1571developers to reuse this interface to provide search within their own apps and 1572allow developers to supply results to the common global search user interface. 1573</p> 1574 1575<p>Android device implementations SHOULD include global search, a single, 1576shared, system-wide search user interface capable of real-time suggestions in 1577response to user input. Device implementations SHOULD implement the APIs that 1578allow developers to reuse this user interface to provide search within their own 1579applications. Device implementations that implement the global search interface 1580MUST implement the APIs that allow third-party applications to add suggestions 1581to the search box when it is run in global search mode. If no third-party 1582applications are installed that make use of this functionality, the default 1583behavior SHOULD be to display web search engine results and suggestions.</p> 1584 1585<p>Android device implementations SHOULD implement an assistant on the device 1586to handle the 1587<a href="http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST">Assist 1588action</a>.</p> 1589 1590<p>Android also includes the 1591<a href="https://developer.android.com/reference/android/app/assist/package-summary.html">Assist 1592APIs</a> to allow applications to elect how much information of the current 1593context is shared with the assistant on the device. Device implementations 1594supporting the Assist action MUST indicate clearly to the end user when the the 1595context is shared by displaying a white light around the edges of the screen. To 1596ensure clear visibility to the end user, the indication MUST meet or exceed the 1597duration and brightness of the Android Open Source Project implementation.</p> 1598 1599<h3 id="3_8_5_toasts">3.8.5. Toasts</h3> 1600 1601 1602<p>Applications can use the <a href="http://developer.android.com/reference/android/widget/Toast.html">“Toast” 1603API</a> to display short non-modal strings to the end user that disappear after 1604a brief period of time. Device implementations MUST display Toasts from 1605applications to end users in some high-visibility manner.</p> 1606 1607<h3 id="3_8_6_themes">3.8.6. Themes</h3> 1608 1609 1610<p>Android provides “themes” as a mechanism for applications to 1611apply styles across an entire Activity or application.</p> 1612 1613<p>Android includes a “Holo” theme family as a set of defined styles 1614for application developers to use if they want to match the 1615<a href="http://developer.android.com/guide/topics/ui/themes.html">Holo theme 1616look and feel</a> as defined by the Android SDK. Device implementations MUST NOT 1617alter any of the 1618<a href="http://developer.android.com/reference/android/R.style.html">Holo 1619theme attributes</a> exposed to applications.</p> 1620 1621<p>Android includes a “Material” theme family as a set of defined 1622styles for application developers to use if they want to match the design 1623theme’s look and feel across the wide variety of different Android device 1624types. Device implementations MUST support the “Material” theme 1625family and MUST NOT alter any of the 1626<a href="http://developer.android.com/reference/android/R.style.html#Theme_Material">Material 1627theme attributes</a> or their assets exposed to applications.</p> 1628 1629<p>Android also includes a “Device Default” theme family as a set of 1630defined styles for application developers to use if they want to match the look 1631and feel of the device theme as defined by the device implementer. Device 1632implementations MAY modify the 1633<a href="http://developer.android.com/reference/android/R.style.html">Device 1634Default theme attributes</a> exposed to applications.</p> 1635 1636<p>Android supports a variant theme with translucent system bars, which allows 1637application developers to fill the area behind the status and navigation bar 1638with their app content. To enable a consistent developer experience in this 1639configuration, it is important the status bar icon style is maintained across 1640different device implementations. Therefore, Android device implementations 1641MUST use white for system status icons (such as signal strength and battery 1642level) and notifications issued by the system, unless the icon is indicating a 1643problematic status or an app requests a light status bar using the 1644SYSTEM_UI_FLAG_LIGHT_STATUS_BAR flag. When an app requests a light status bar, 1645Android device implementations MUST change the color of the system status icons 1646to black (for details, refer to 1647<a href="http://developer.android.com/reference/android/R.style.html">R.style</a>).</p> 1648 1649<h3 id="3_8_7_live_wallpapers">3.8.7. Live Wallpapers</h3> 1650 1651 1652<p>Android defines a component type and corresponding API and lifecycle that 1653allows applications to expose one or more 1654<a href="http://developer.android.com/reference/android/service/wallpaper/WallpaperService.html">“Live 1655Wallpapers”</a> to the end user. Live wallpapers are animations, patterns, 1656or similar images with limited input capabilities that display as a wallpaper, 1657behind other applications.</p> 1658 1659<p>Hardware is considered capable of reliably running live wallpapers if it can 1660run all live wallpapers, with no limitations on functionality, at a reasonable 1661frame rate with no adverse effects on other applications. If limitations in the 1662hardware cause wallpapers and/or applications to crash, malfunction, consume 1663excessive CPU or battery power, or run at unacceptably low frame rates, the 1664hardware is considered incapable of running live wallpaper. As an example, some 1665live wallpapers may use an OpenGL 2.0 or 3.x context to render their content. 1666Live wallpaper will not run reliably on hardware that does not support multiple 1667OpenGL contexts because the live wallpaper use of an OpenGL context may 1668conflict with other applications that also use an OpenGL context.</p> 1669 1670<p>Device implementations capable of running live wallpapers reliably as 1671described above SHOULD implement live wallpapers, and when implemented MUST 1672report the platform feature flag android.software.live_wallpaper.</p> 1673 1674<h3 id="3_8_8_activity_switching">3.8.8. Activity Switching</h3> 1675 1676<div class="note"> 1677<p>As the Recent function navigation key is OPTIONAL, the requirements to 1678implement the overview screen is OPTIONAL for Android Television devices and 1679Android Watch devices.</p> 1680</div> 1681 1682 1683<p>The upstream Android source code includes the 1684<a href="http://developer.android.com/guide/components/recents.html">overview 1685screen</a>, a system-level user interface for task switching and displaying 1686recently accessed activities and tasks using a thumbnail image of the 1687application’s graphical state at the moment the user last left the 1688application. Device implementations including the recents function navigation 1689key as detailed in <a href="#7_2_3_navigation_keys">section 7.2.3</a> MAY alter 1690the interface but MUST meet the following requirements:</p> 1691 1692<ul> 1693 <li>MUST display affiliated recents as a group that moves together.</li> 1694 <li>MUST support at least up to 20 displayed activities.</li> 1695 <li>MUST at least display the title of 4 activities at a time.</li> 1696 <li>SHOULD display highlight color, icon, screen title in recents.</li> 1697 <li>MUST implement the 1698 <a href="http://developer.android.com/about/versions/android-5.0.html#ScreenPinning">screen 1699 pinning behavior</a>] and provide the user with a settings menu to toggle the 1700 feature.</li> 1701 <li>SHOULD display a closing affordance ("x") but MAY delay this until user 1702 interacts with screens.</li> 1703</ul> 1704 1705<p>Device implementations are STRONGLY RECOMMENDED to use the upstream Android 1706user interface (or a similar thumbnail-based interface) for the overview screen. 1707</p> 1708 1709<h3 id="3_8_9_input_management">3.8.9. Input Management</h3> 1710 1711 1712<p>Android includes support for 1713<a href="http://developer.android.com/guide/topics/text/creating-input-method.html">Input 1714Management</a> and support for third-party input method editors. Device 1715implementations that allow users to use third-party input methods on the device 1716MUST declare the platform feature android.software.input_methods and support IME 1717APIs as defined in the Android SDK documentation.</p> 1718 1719<p>Device implementations that declare the 1720android.software.input_methods feature MUST provide a user-accessible mechanism 1721to add and configure third-party input methods. Device implementations MUST 1722display the settings interface in response to the 1723android.settings.INPUT_METHOD_SETTINGS intent.</p> 1724 1725<h3 id="3_8_10_lock_screen_media_control">3.8.10. Lock Screen Media Control</h3> 1726 1727 1728<p>The Remote Control Client API is deprecated from Android 5.0 in favor of the 1729<a href="http://developer.android.com/reference/android/app/Notification.MediaStyle.html">Media 1730Notification Template</a> that allows media applications to integrate with 1731playback controls that are displayed on the lock screen. Device implementations 1732that support a lock screen, unless an Android Automotive or Watch 1733implementation, MUST display the Lockscreen Notifications including the Media 1734Notification Template.</p> 1735 1736<h3 id="3_8_11_dreams">3.8.11. Dreams</h3> 1737 1738 1739<p>Android includes support for interactive screensavers called 1740<a href="http://developer.android.com/reference/android/service/dreams/DreamService.html">Dreams</a>. 1741Dreams allows users to interact with applications when a device connected to 1742a power source is idle or docked in a desk dock. Android Watch devices MAY 1743implement Dreams, but other types of device implementations SHOULD include 1744support for Dreams and provide a settings option for users to configure Dreams 1745in response to the android.settings.DREAM_SETTINGS intent.</p> 1746 1747<h3 id="3_8_12_location">3.8.12. Location</h3> 1748 1749 1750<p>When a device has a hardware sensor (e.g. GPS) that is capable of providing 1751the location coordinates, 1752<a href="http://developer.android.com/reference/android/provider/Settings.Secure.html#LOCATION_MODE">location 1753modes</a> MUST be displayed in the Location menu within Settings.</p> 1754 1755<h3 id="3_8_13_unicode_and_font">3.8.13. Unicode and Font</h3> 1756 1757 1758<p>Android includes support for color emoji characters. When Android device 1759implementations include an IME, devices SHOULD provide an input method to the 1760user for the Emoji characters defined in 1761<a href="http://www.unicode.org/versions/Unicode6.1.0/">Unicode 6.1</a>. All 1762devices MUST be capable of rendering these emoji characters in color glyph.</p> 1763 1764<p>Android includes support for Roboto 2 font with different 1765weights—sans-serif-thin, sans-serif-light, sans-serif-medium, 1766sans-serif-black, sans-serif-condensed, sans-serif-condensed-light—which 1767MUST all be included for the languages available on the device and full Unicode 17687.0 coverage of Latin, Greek, and Cyrillic, including the Latin Extended A, B, 1769C, and D ranges, and all glyphs in the currency symbols block of Unicode 7.0. 1770</p> 1771 1772<h2 id="3_9_device_administration">3.9. Device Administration</h2> 1773 1774<p>Android includes features that allow security-aware applications to perform 1775device administration functions at the system level, such as enforcing password 1776policies or performing remote wipe, through the 1777<a href="http://developer.android.com/guide/topics/admin/device-admin.html">Android 1778Device Administration API</a>]. Device implementations MUST provide an 1779implementation of the <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html">DevicePolicyManager</a> 1780class. Device implementations that include support for PIN (numeric) or PASSWORD 1781(alphanumeric) based lock screens MUST support the full range of 1782<a href="http://developer.android.com/guide/topics/admin/device-admin.html">device 1783administration</a> policies defined in the Android SDK documentation and report 1784the platform feature android.software.device_admin.</p> 1785 1786<h3 id="3_9_1_device_provisioning">3.9.1 Device Provisioning</h3> 1787 1788<h4 id="3_9_1_1_device_owner_provisioning">3.9.1.1 Device owner provisioning</h4> 1789<p>If a device implementation declares the android.software.device_admin 1790feature, the out of box setup flow MUST make it possible to enroll a Device 1791Policy Controller (DPC) application as the 1792<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isDeviceOwnerApp(java.lang.String)">Device 1793Owner app</a>. Device implementations MAY have a preinstalled application 1794performing device administration functions but this application MUST NOT be set 1795as the Device Owner app without explicit consent or action from the user or the 1796administrator of the device.</p> 1797 1798<p>The device owner provisioning process (the flow initiated by 1799<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_DEVICE">android.app.action.PROVISION_MANAGED_DEVICE</a>) 1800user experience MUST align with the AOSP implementation.</p> 1801 1802<p>If the device implementation reports android.hardware.nfc, it MUST have NFC 1803enabled, even during the out-of-box setup flow, in order to allow for 1804<a href="https://source.android.com/devices/tech/admin/provision.html#device_owner_provisioning_via_nfc">NFC 1805provisioning of Device owners</a>.</p> 1806 1807<h4 id="3_9_1_2_managed_profile_provisioning">3.9.1.2 Managed profile 1808provisioning</h4> 1809<p>If a device implementation declares the android.software.managed_users, 1810it MUST be possible to enroll a Device Policy Controller (DPC) application 1811as the 1812<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isProfileOwnerApp(java.lang.String)">owner 1813of a new Managed Profile</a>.</p> 1814 1815<p>The managed profile provisioning process (the flow initiated by 1816<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_PROFILE">android.app.action.PROVISION_MANAGED_PROFILE</a>) 1817user experience MUST align with the AOSP implementation.</p> 1818 1819 1820<h2 id="3_9_2_managed_profile_support">3.9.2 Managed Profile Support</h2> 1821 1822<p>Managed profile capable devices are those devices that:</p> 1823<ul> 1824 <li>Declare android.software.device_admin (see 1825 <a href="#3_9_device_administration">section 3.9 Device Administration</a>). 1826 </li> 1827 <li>Are not low RAM devices (see 1828 <a href="#7_6_1_minimum_memory_and_storage">section 7.6.1</a>).</li> 1829 <li>Allocate internal (non-removable) storage as shared storage (see 1830 <a href="#7_6_2_application_shared_storage">section 7.6.2</a>).</li> 1831</ul> 1832<p>Managed profile capable devices MUST:</p> 1833<ul> 1834 <li>Declare the platform feature flag android.software.managed_users.</li> 1835 <li>Support managed profiles via the android.app.admin.DevicePolicyManager APIs.</li> 1836 <li>Allow one and only 1837 <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_PROFILE">one 1838 managed profile to be created</a>.</li> 1839 <li>Use an icon badge (similar to the AOSP upstream work badge) to represent 1840 the managed applications and widgets and other badged UI elements like Recents 1841 & Notifications.</li> 1842 <li>Display a notification icon (similar to the AOSP upstream work badge) to 1843 indicate when user is within a managed profile application.</li> 1844 <li>Display a toast indicating that the user is in the managed profile if and 1845 when the device wakes up (ACTION_USER_PRESENT) and the foreground application 1846 is within the managed profile.</li> 1847 <li>Where a managed profile exists, show a visual affordance in the Intent 1848 'Chooser' to allow the user to forward the intent from the managed profile to 1849 the primary user or vice versa, if enabled by the Device Policy Controller. 1850 </li> 1851 <li>Where a managed profile exists, expose the following user affordances for 1852 both the primary user and the managed profile: 1853 <ul> 1854 <li>Separate accounting for battery, location, mobile data and storage usage 1855 for the primary user and managed profile.</li> 1856 <li>Independent management of VPN Applications installed within the primary 1857 user or managed profile.</li> 1858 <li>Independent management of applications installed within the primary user 1859 or managed profile.</li> 1860 <li>Independent management of accounts within the primary user or managed 1861 profile.</li> 1862 </ul> 1863 </li> 1864 <li>Ensure the default dialer can look up caller information from the managed 1865 profile (if one exists) alongside those from the primary profile, if the 1866 Device Policy Controller permits it.</li> 1867 <li>MUST ensure that it satisfies all the security requirements applicable for 1868 a device with multiple users enabled (see 1869 <a href="#9_5_multi-user_support">section 9.5</a>), even though the managed 1870 profile is not counted as another user in addition to the primary user.</li> 1871</ul> 1872 1873<h2 id="3_10_accessibility">3.10. Accessibility</h2> 1874 1875 1876<p>Android provides an accessibility layer that helps users with disabilities to 1877navigate their devices more easily. In addition, Android provides platform APIs 1878that enable 1879<a href="http://developer.android.com/reference/android/accessibilityservice/AccessibilityService.html">accessibility 1880service implementations</a> to receive callbacks for user and system events and 1881generate alternate feedback mechanisms, such as text-to-speech, haptic feedback, 1882and trackball/d-pad navigation.</p> 1883 1884<p>Device implementations include the following requirements:</p> 1885 1886<ul> 1887 <li>Android Automotive implementations SHOULD provide an implementation of the 1888 Android accessibility framework consistent with the default Android 1889 implementation.</li> 1890 <li>Device implementations (Android Automotive excluded) MUST provide an 1891 implementation of the Android accessibility framework consistent with the 1892 default Android implementation.</li> 1893 <li>Device implementations (Android Automotive excluded) MUST support 1894 third-party accessibility service implementations through the 1895 <a href="http://developer.android.com/reference/android/view/accessibility/package-summary.html">android.accessibilityservice APIs</a>. 1896 </li> 1897 <li>Device implementations (Android Automotive excluded) MUST generate 1898 AccessibilityEvents and deliver these events to all registered 1899 AccessibilityService implementations in a manner consistent with the default 1900 Android implementation</li> 1901 <li>Device implementations (Android Automotive and Android Watch devices with 1902 no audio output excluded), MUST provide a user-accessible mechanism to enable 1903 and disable accessibility services, and MUST display this interface in 1904 response to the android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS 1905 intent.</li> 1906</ul> 1907 1908<p>Additionally, device implementations SHOULD provide an implementation of an 1909accessibility service on the device, and SHOULD provide a mechanism for users 1910to enable the accessibility service during device setup. An open source 1911implementation of an accessibility service is available from the 1912<a href="http://code.google.com/p/eyes-free/">Eyes Free project</a>.</p> 1913 1914<h2 id="3_11_text-to-speech">3.11. Text-to-Speech</h2> 1915 1916 1917<p>Android includes APIs that allow applications to make use of text-to-speech 1918(TTS) services and allows service providers to provide implementations of TTS 1919services. Device implementations reporting the feature 1920android.hardware.audio.output MUST meet these requirements related to the 1921<a href="http://developer.android.com/reference/android/speech/tts/package-summary.html">Android 1922TTS framework</a>.</p> 1923 1924<p>Android Automotive implementations:</p> 1925<ul> 1926 <li>MUST support the Android TTS framework APIs.</li> 1927 <li>MAY support installation of third-party TTS engines. If supported, 1928 partners MUST provide a user-accessible interface that allows the user to 1929 select a TTS engine for use at system level.</li> 1930</ul> 1931 1932<p>All other device implementations:</p> 1933 1934<ul> 1935 <li>MUST support the Android TTS framework APIs and SHOULD include a TTS 1936 engine supporting the languages available on the device. Note that the 1937 upstream Android open source software includes a full-featured TTS engine 1938 implementation. 1939 <li>MUST support installation of third-party TTS engines. 1940 <li>MUST provide a user-accessible interface that allows users to select a TTS 1941 engine for use at the system level. 1942</ul> 1943 1944<h2 id="3_12_tv_input_framework">3.12. TV Input Framework</h2> 1945 1946 1947<p>The <a href="http://source.android.com/devices/tv/index.html">Android 1948Television Input Framework (TIF)</a> simplifies the delivery of live content to 1949Android Television devices. TIF provides a standard API to create input modules 1950that control Android Television devices. Android Television device 1951implementations MUST support TV Input Framework.</p> 1952 1953<p>Device implementations that support TIF MUST declare the platform feature 1954android.software.live_tv.</p> 1955 1956<h3 id="3_12_1_tv_app">3.12.1. TV App</h3> 1957 1958<p>Any device implementation that declares support for Live TV MUST have an 1959installed TV application (TV App). The Android Open Source Project provides an 1960implementation of the TV App.</p> 1961 1962<p>The TV App MUST provide facilities to install and use 1963<a href="http://developer.android.com/reference/android/media/tv/TvContract.Channels.html">TV 1964Channels</a> and meet the following requirements:</p> 1965 1966<ul> 1967 <li>Device implementations MUST allow third-party TIF-based inputs 1968 (<a href="https://source.android.com/devices/tv/index.html#third-party_input_example">third-party 1969 inputs</a>) to be installed and managed.</li> 1970 <li>Device implementations MAY provide visual separation between pre-installed 1971 <a href="https://source.android.com/devices/tv/index.html#tv_inputs">TIF-based 1972 inputs</a> (installed inputs) and third-party inputs.</li> 1973 <li>Device implementations MUST NOT display the third-party inputs more than a 1974 single navigation action away from the TV App (i.e. expanding a list of 1975 third-party inputs from the TV App).</li> 1976</ul> 1977 1978<h4 id="3_12_1_1_electronic_program_guide">3.12.1.1. Electronic Program 1979Guide</h4> 1980 1981<p>Android Television device implementations MUST show an informational and 1982interactive overlay, which MUST include an electronic program guide (EPG) 1983generated from the values in the 1984<a href="https://developer.android.com/reference/android/media/tv/TvContract.Programs.html">TvContract.Programs</a> 1985fields. The EPG MUST meet the following requirements:</p> 1986 1987<ul> 1988 <li>The EPG MUST display information from all installed inputs and third-party 1989 inputs.</li> 1990 <li>The EPG MAY provide visual separation between the installed inputs and 1991 third-party inputs.</li> 1992 <li>The EPG is STRONGLY RECOMMENDED to display installed inputs and 1993 third-party inputs with equal prominence. The EPG MUST NOT display the 1994 third-party inputs more than a single navigation action away from the 1995 installed inputs on the EPG.</li> 1996 <li>On channel change, device implementations MUST display EPG data for the 1997 currently playing program.</li> 1998</ul> 1999 2000<h4 id="3_12_1_2_navigation">3.12.1.2. Navigation</h4> 2001 2002<p>Android Television device input devices (i.e. remote control, remote control 2003application, or game controller) MUST allow navigation to all actionable 2004sections of the screen via the D-pad. D-pad up and down MUST be used to change 2005live TV channels when there is no actionable section on the screen.</p> 2006 2007<p>The TV App SHOULD pass key events to HDMI inputs through CEC.</p> 2008 2009<h4 id="3_12_1_3_tv_input_app_linking">3.12.1.3. TV input app linking</h4> 2010 2011<p>Android Television device implementations MUST support 2012<a href="http://developer.android.com/reference/android/media/tv/TvContract.Channels.html#COLUMN_APP_LINK_INTENT_URI">TV 2013input app linking</a>, which allows all inputs to provide activity links from 2014the current activity to another activity (i.e. a link from live programming to 2015related content). The TV App MUST show TV input app linking when it is provided. 2016</p> 2017 2018<h1 id="4_application_packaging_compatibility">4. Application Packaging 2019Compatibility</h1> 2020 2021 2022<p>Device implementations MUST install and run Android “.apk” files 2023as generated by the “aapt” tool included in the 2024<a href="http://developer.android.com/tools/help/index.html">official Android 2025SDK</a>.</p> 2026 2027<p>Devices implementations MUST NOT extend either the 2028<a href="http://developer.android.com/guide/components/fundamentals.html">.apk</a>, 2029<a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">Android 2030Manifest</a>, <a href="https://android.googlesource.com/platform/dalvik/">Dalvik 2031bytecode</a>, or RenderScript bytecode formats in such a way that would prevent 2032those files from installing and running correctly on other compatible devices. 2033</p> 2034 2035<h1 id="5_multimedia_compatibility">5. Multimedia Compatibility</h1> 2036 2037 2038<h2 id="5_1_media_codecs">5.1. Media Codecs</h2> 2039 2040 2041<p>Device implementations MUST support the 2042<a href="http://developer.android.com/guide/appendix/media-formats.html">core 2043media formats</a> specified in the Android SDK documentation except where 2044explicitly permitted in this document. Specifically, device implementations MUST 2045support the media formats, encoders, decoders, file types, and container formats 2046defined in the tables below and reported via 2047<a href="http://developer.android.com/reference/android/media/MediaCodecList.html">MediaCodecList</a>. 2048Device implementations MUST also be able to decode all profiles reported in its 2049<a href="http://developer.android.com/reference/android/media/CamcorderProfile.html">CamcorderProfile</a> 2050and MUST be able to decode all formats it can encode. All of these codecs are 2051provided as software implementations in the preferred Android implementation 2052from the Android Open Source Project.</p> 2053 2054<p>Please note that neither Google nor the Open Handset Alliance make any 2055representation that these codecs are free from third-party patents. Those 2056intending to use this source code in hardware or software products are advised 2057that implementations of this code, including in open source software or 2058shareware, may require patent licenses from the relevant patent holders.</p> 2059 2060<h3 id="5_1_1_audio_codecs">5.1.1. Audio Codecs</h3> 2061 2062<table> 2063 <tr> 2064 <th>Format/Codec</th> 2065 <th>Encoder</th> 2066 <th>Decoder</th> 2067 <th>Details</th> 2068 <th>Supported File Types/Container Formats</th> 2069 </tr> 2070 <tr> 2071 <td>MPEG-4 AAC Profile<br /> 2072 2073(AAC LC)</td> 2074 <td>REQUIRED<sup>1</sup></td> 2075 <td>REQUIRED</td> 2076 <td>Support for mono/stereo/5.0/5.1<sup>2</sup> content with standard 2077 sampling rates from 8 to 48 kHz.</td> 2078 <td> 2079 <ul> 2080 <li class="table_list">3GPP (.3gp)</li> 2081 <li class="table_list">MPEG-4 (.mp4, .m4a)</li> 2082 <li class="table_list">ADTS raw AAC (.aac, decode in Android 3.1+, encode in 2083 Android 4.0+, ADIF not supported)</li> 2084 <li class="table_list">MPEG-TS (.ts, not seekable, Android 3.0+)</li></ul> 2085 </td> 2086 </tr> 2087 <tr> 2088 <td>MPEG-4 HE AAC Profile (AAC+)</td> 2089 <td>REQUIRED<sup>1</sup><br>(Android 4.1+)</td> 2090 <td>REQUIRED</td> 2091 <td>Support for mono/stereo/5.0/5.1<sup>2</sup> content with standard 2092 sampling rates from 16 to 48 kHz.</td> 2093 <td></td> 2094 </tr> 2095 <tr> 2096 <td>MPEG-4 HE AACv2<br /> 2097 2098Profile (enhanced AAC+)</td> 2099 <td> </td> 2100 <td>REQUIRED</td> 2101 <td>Support for mono/stereo/5.0/5.1<sup>2</sup> content with standard 2102 sampling rates from 16 to 48 kHz.</td> 2103 <td></td> 2104 </tr> 2105 <tr> 2106 <td>AAC ELD (enhanced low delay AAC)</td> 2107 <td>REQUIRED<sup>1</sup> <br /> 2108 2109(Android 4.1+)</td> 2110 <td>REQUIRED<br /> 2111 2112(Android 4.1+)</td> 2113 <td>Support for mono/stereo content with standard sampling rates from 16 to 2114 48 kHz.</td> 2115 <td></td> 2116 </tr> 2117 <tr> 2118 <td>AMR-NB</td> 2119 <td>REQUIRED<sup>3</sup></td> 2120 <td>REQUIRED<sup>3</sup></td> 2121 <td>4.75 to 12.2 kbps sampled @ 8 kHz</td> 2122 <td>3GPP (.3gp)</td> 2123 </tr> 2124 <tr> 2125 <td>AMR-WB</td> 2126 <td>REQUIRED<sup>3</sup></td> 2127 <td>REQUIRED<sup>3</sup></td> 2128 <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16 kHz</td> 2129 <td></td> 2130 </tr> 2131 <tr> 2132 <td>FLAC</td> 2133 <td></td> 2134 <td>REQUIRED <br>(Android 3.1+)</td> 2135 <td>Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1 2136 kHz is RECOMMENDED on devices with 44.1 kHz output, as the 48 to 44.1 kHz 2137 downsampler does not include a low-pass filter). 16-bit RECOMMENDED; no 2138 dither applied for 24-bit.</td> 2139 <td>FLAC (.flac) only</td> 2140 </tr> 2141 <tr> 2142 <td>MP3</td> 2143 <td></td> 2144 <td>REQUIRED</td> 2145 <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bitrate (VBR)</td> 2146 <td>MP3 (.mp3)</td> 2147 </tr> 2148 <tr> 2149 <td>MIDI</td> 2150 <td></td> 2151 <td>REQUIRED</td> 2152 <td>MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for 2153 ringtone formats RTTTL/RTX, OTA, and iMelody</td> 2154 <td><ul> 2155 <li class="table_list">Type 0 and 1 (.mid, .xmf, .mxmf)</li> 2156 <li class="table_list">RTTTL/RTX (.rtttl, .rtx)</li> 2157 <li class="table_list">OTA (.ota)</li> 2158 <li class="table_list">iMelody (.imy)</li></ul></td> 2159 </tr> 2160 <tr> 2161 <td>Vorbis</td> 2162 <td></td> 2163 <td>REQUIRED</td> 2164 <td></td> 2165 <td><ul> 2166 <li class="table_list">Ogg (.ogg)</li> 2167 <li class="table_list">Matroska (.mkv, Android 4.0+)</li></ul></td> 2168 </tr> 2169 <tr> 2170 <td>PCM/WAVE</td> 2171 <td>REQUIRED<sup>4</sup><br> (Android 4.1+)</td> 2172 <td>REQUIRED</td> 2173 <td>16-bit linear PCM (rates up to limit of hardware). Devices MUST support 2174 sampling rates for raw PCM recording at 8000, 11025, 16000, and 44100 Hz 2175 frequencies.</td> 2176 <td>WAVE (.wav)</td> 2177 </tr> 2178 <tr> 2179 <td>Opus</td> 2180 <td></td> 2181 <td>REQUIRED<br> (Android 5.0+)</td> 2182 <td></td> 2183 <td>Matroska (.mkv)</td> 2184 </tr> 2185</table> 2186 2187 2188<p class="table_footnote"> 1 Required for device implementations that define 2189android.hardware.microphone but optional for Android Watch device 2190implementations.</p> 2191 2192<p class="table_footnote">2 Only downmix of 5.0/5.1 content is required; 2193recording or rendering more than 2 channels is optional.</p> 2194 2195<p class="table_footnote">3 Required for Android Handheld device 2196implementations.</p> 2197 2198<p class="table_footnote">4 Required for device implementations that define 2199android.hardware.microphone, including Android Watch device implementations.</p> 2200 2201<h3 id="5_1_2_image_codecs">5.1.2. Image Codecs</h3> 2202 2203<table> 2204 <tr> 2205 <th>Format/Codec</th> 2206 <th>Encoder</th> 2207 <th>Decoder</th> 2208 <th>Details</th> 2209 <th>Supported File Types/Container Formats</th> 2210 </tr> 2211 <tr> 2212 <td>JPEG</td> 2213 <td>REQUIRED</td> 2214 <td>REQUIRED</td> 2215 <td>Base+progressive</td> 2216 <td>JPEG (.jpg)</td> 2217 </tr> 2218 <tr> 2219 <td>GIF</td> 2220 <td></td> 2221 <td>REQUIRED</td> 2222 <td></td> 2223 <td>GIF (.gif)</td> 2224 </tr> 2225 <tr> 2226 <td>PNG</td> 2227 <td>REQUIRED</td> 2228 <td>REQUIRED</td> 2229 <td></td> 2230 <td>PNG (.png)</td> 2231 </tr> 2232 <tr> 2233 <td>BMP</td> 2234 <td></td> 2235 <td>REQUIRED</td> 2236 <td></td> 2237 <td>BMP (.bmp)</td> 2238 </tr> 2239 <tr> 2240 <td>WebP</td> 2241 <td>REQUIRED</td> 2242 <td>REQUIRED</td> 2243 <td></td> 2244 <td>WebP (.webp)</td> 2245 </tr> 2246</table> 2247 2248 2249<h3 id="5_1_3_video_codecs">5.1.3. Video Codecs</h3> 2250 2251<table> 2252 <tr> 2253 <th>Format/Codec</th> 2254 <th>Encoder</th> 2255 <th>Decoder</th> 2256 <th>Details</th> 2257 <th>Supported File Types/<br>Container Formats</th> 2258 </tr> 2259 <tr> 2260 <td>H.263</td> 2261 <td>REQUIRED<sup>1</sup></td> 2262 <td>REQUIRED<sup>2</sup></td> 2263 <td></td> 2264 <td><ul> 2265 <li class="table_list">3GPP (.3gp)</li> 2266 <li class="table_list">MPEG-4 (.mp4)</li></ul></td> 2267 </tr> 2268 <tr> 2269 <td>H.264 AVC</td> 2270 <td>REQUIRED<sup>2</sup></td> 2271 <td>REQUIRED<sup>2</sup></td> 2272 <td>See <a href="#5_2_video_encoding">section 5.2 </a>and 2273 <a href="#5_3_video_decoding">5.3</a> for details</td> 2274 <td><ul> 2275 <li class="table_list">3GPP (.3gp)</li> 2276 <li class="table_list">MPEG-4 (.mp4)</li> 2277 <li class="table_list">MPEG-2 TS (.ts, AAC audio only, not seekable, Android 2278 3.0+)</li></ul></td> 2279 </tr> 2280 <tr> 2281 <td>H.265 HEVC</td> 2282 <td></td> 2283 <td>REQUIRED<sup>5</sup></td> 2284 <td>See <a href="#5_3_video_decoding">section 5.3</a> for details</td> 2285 <td>MPEG-4 (.mp4)</td> 2286 </tr> 2287<tr> 2288 <td>MPEG-2</td> 2289 <td></td> 2290 <td>STRONGLY RECOMMENDED<sup>6</sup></td> 2291 <td>Main Profile</td> 2292 <td>MPEG2-TS</td> 2293</tr> 2294 <tr> 2295 <td>MPEG-4 SP</td> 2296 <td></td> 2297 <td>REQUIRED<sup>2</sup></td> 2298 <td></td> 2299 <td>3GPP (.3gp)</td> 2300 </tr> 2301 <tr> 2302 <td>VP8<sup>3</sup></td> 2303 <td>REQUIRED<sup>2</sup><br /> 2304 2305(Android 4.3+)</td> 2306 <td>REQUIRED<sup>2</sup><br /> 2307 2308(Android 2.3.3+)</td> 2309 <td>See <a href="#5_2_video_encoding">section 5.2</a> and 2310 <a href="#5_3_video_decoding">5.3</a> for details</td> 2311 <td><ul> 2312 <li class="table_list"><a href="http://www.webmproject.org/">WebM 2313 (.webm)</a></li> 2314 <li class="table_list">Matroska (.mkv, Android 4.0+)<sup>4</sup></li></ul> 2315 </td> 2316 </tr> 2317 <tr> 2318 <td>VP9</td> 2319 <td></td> 2320 <td>REQUIRED<sup>2</sup><br> (Android 4.4+)</td> 2321 <td>See <a href="#5_3_video_decoding">section 5.3</a> for details</td> 2322 <td><ul> 2323 <li class="table_list"><a href="http://www.webmproject.org/">WebM 2324 (.webm)</a></li> 2325 <li class="table_list">Matroska (.mkv, Android 4.0+)<sup>4</sup></li></ul> 2326 </td> 2327 </tr> 2328</table> 2329 2330 2331<p class="table_footnote">1 Required for device implementations that include 2332camera hardware and define android.hardware.camera or 2333android.hardware.camera.front.</p> 2334 2335<p class="table_footnote">2 Required for device implementations except Android 2336Watch devices. </p> 2337 2338<p class="table_footnote">3 For acceptable quality of web video streaming and 2339video-conference services, device implementations SHOULD use a hardware VP8 2340codec that meets the 2341<a href="http://www.webmproject.org/hardware/rtc-coding-requirements/">requirements</a>. 2342</p> 2343 2344<p class="table_footnote">4 Device implementations SHOULD support writing 2345Matroska WebM files.</p> 2346 2347<p class="table_footnote">5 STRONGLY RECOMMENDED for Android Automotive, 2348optional for Android Watch, and required for all other device types.</p> 2349 2350<p class="table_footnote">6 Applies only to Android Television device 2351implementations.</p> 2352 2353<h2 id="5_2_video_encoding">5.2. Video Encoding</h2> 2354 2355<div class="note"> 2356<p>Video codecs are optional for Android Watch device implementations.</p> 2357</div> 2358 2359<p>Android device implementations with H.263 encoders MUST support Baseline 2360Profile Level 45.</p> 2361 2362<p>Android device implementations with H.264 codec support MUST support Baseline 2363Profile Level 3 and the following SD (Standard Definition) video encoding 2364profiles and SHOULD support Main Profile Level 4 and the following HD (High 2365Definition) video encoding profiles. Android Television devices are STRONGLY 2366RECOMMENDED to encode HD 1080p video at 30 fps.</p> 2367<table> 2368 <tr> 2369 <th></th> 2370 <th>SD (Low quality)</th> 2371 <th>SD (High quality)</th> 2372 <th>HD 720p<sup>1</sup></th> 2373 <th>HD 1080p<sup>1</sup></th> 2374 </tr> 2375 <tr> 2376 <th>Video resolution</th> 2377 <td>320 x 240 px</td> 2378 <td>720 x 480 px</td> 2379 <td>1280 x 720 px</td> 2380 <td>1920 x 1080 px</td> 2381 </tr> 2382 <tr> 2383 <th>Video frame rate</th> 2384 <td>20 fps</td> 2385 <td>30 fps</td> 2386 <td>30 fps</td> 2387 <td>30 fps</td> 2388 </tr> 2389 <tr> 2390 <th>Video bitrate</th> 2391 <td>384 Kbps</td> 2392 <td>2 Mbps</td> 2393 <td>4 Mbps</td> 2394 <td>10 Mbps</td> 2395 </tr> 2396</table> 2397 2398 2399<p class="table_footnote">1 When supported by hardware, but STRONGLY RECOMMENDED 2400for Android Television devices.</p> 2401 2402<p>Android device implementations with VP8 codec support MUST support the SD 2403video encoding profiles and SHOULD support the following HD (High Definition) 2404video encoding profiles.</p> 2405<table> 2406 <tr> 2407 <th></th> 2408 <th>SD (Low quality)</th> 2409 <th>SD (High quality)</th> 2410 <th>HD 720p<sup>1</sup></th> 2411 <th>HD 1080p<sup>1</sup></th> 2412 </tr> 2413 <tr> 2414 <th>Video resolution</th> 2415 <td>320 x 180 px</td> 2416 <td>640 x 360 px</td> 2417 <td>1280 x 720 px</td> 2418 <td>1920 x 1080 px</td> 2419 </tr> 2420 <tr> 2421 <th>Video frame rate</th> 2422 <td>30 fps</td> 2423 <td>30 fps</td> 2424 <td>30 fps</td> 2425 <td>30 fps</td> 2426 </tr> 2427 <tr> 2428 <th>Video bitrate</th> 2429 <td>800 Kbps </td> 2430 <td>2 Mbps</td> 2431 <td>4 Mbps</td> 2432 <td>10 Mbps</td> 2433 </tr> 2434</table> 2435 2436<p class="table_footnote">1 When supported by hardware.</p> 2437 2438<h2 id="5_3_video_decoding">5.3. Video Decoding</h2> 2439 2440<div class="note"> 2441<p>Video codecs are optional for Android Watch device implementations.</p> 2442</div> 2443 2444<p>Device implementations MUST support dynamic video resolution and frame rate 2445switching through the standard Android APIs within the same stream for all VP8, 2446VP9, H.264, and H.265 codecs in real time and up to the maximum resolution 2447supported on the device.</p> 2448 2449<p>Android device implementations with H.263 decoders MUST support Baseline 2450Profile Level 30.</p> 2451 2452<p>Android device implementations with MPEG-4 decoders MUST support Simple 2453Profile Level 3.</p> 2454 2455<p>Android device implementations with H.264 decoders MUST support Main Profile 2456Level 3.1 and the following SD video decoding profiles and SHOULD support the 2457HD decoding profiles. Android Television devices MUST support High Profile 2458Level 4.2 and the HD 1080p decoding profile.</p> 2459<table> 2460 <tr> 2461 <th></th> 2462 <th>SD (Low quality)</th> 2463 <th>SD (High quality)</th> 2464 <th>HD 720p<sup>1</sup></th> 2465 <th>HD 1080p<sup>1</sup></th> 2466 </tr> 2467 <tr> 2468 <th>Video resolution</th> 2469 <td>320 x 240 px</td> 2470 <td>720 x 480 px</td> 2471 <td>1280 x 720 px</td> 2472 <td>1920 x 1080 px</td> 2473 </tr> 2474 <tr> 2475 <th>Video frame rate</th> 2476 <td>30 fps</td> 2477 <td>30 fps</td> 2478 <td>60 fps</td> 2479 <td>30 fps / 60 fps<sup>2</sup></td> 2480 </tr> 2481 <tr> 2482 <th>Video bitrate</th> 2483 <td>800 Kbps </td> 2484 <td>2 Mbps</td> 2485 <td>8 Mbps</td> 2486 <td>20 Mbps</td> 2487 </tr> 2488</table> 2489 2490 2491<p class="table_footnote">1 REQUIRED for when the height as reported by the 2492Display.getSupportedModes() method is not smaller than the video resolution.</p> 2493 2494<p class="table_footnote">2 REQUIRED for Android Television device 2495implementations.</p> 2496 2497<p>Android device implementations, when supporting VP8 codec as described in 2498<a href="#5_1_3_video_codecs">section 5.1.3</a>, MUST support the following SD 2499decoding profiles and SHOULD support the HD decoding profiles. Android 2500Television devices MUST support the HD 1080p decoding profile.</p> 2501<table> 2502 <tr> 2503 <th></th> 2504 <th>SD (Low quality)</th> 2505 <th>SD (High quality)</th> 2506 <th>HD 720p<sup>1</sup></th> 2507 <th>HD 1080p<sup>1</sup></th> 2508 </tr> 2509 <tr> 2510 <th>Video resolution</th> 2511 <td>320 x 180 px</td> 2512 <td>640 x 360 px</td> 2513 <td>1280 x 720 px</td> 2514 <td>1920 x 1080 px</td> 2515 </tr> 2516 <tr> 2517 <th>Video frame rate</th> 2518 <td>30 fps</td> 2519 <td>30 fps</td> 2520 <td>30 fps / 60 fps<sup>2</sup></td> 2521 <td>30 / 60 fps<sup>2</sup></td> 2522 </tr> 2523 <tr> 2524 <th>Video bitrate</th> 2525 <td>800 Kbps </td> 2526 <td>2 Mbps</td> 2527 <td>8 Mbps</td> 2528 <td>20 Mbps</td> 2529 </tr> 2530</table> 2531 2532<p class="table_footnote">1 REQUIRED for when the height as reported by the 2533Display.getSupportedModes() method is not smaller than the video resolution.</p> 2534 2535<p class="table_footnote">2 REQUIRED for Android Television device 2536implementations.</p> 2537 2538<p>Android device implementations, when supporting VP9 codec as described in 2539<a href="#5_1_3_video_codecs">section 5.1.3</a>, MUST support the following SD 2540video decoding profiles and SHOULD support the HD decoding profiles. Android 2541Television devices are STRONGLY RECOMMENDED to support the HD 1080p decoding 2542profile and SHOULD support the UHD decoding profile. When the UHD video decoding 2543profile is supported, it MUST support 8-bit color depth and SHOULD support VP9 2544Profile 2 (10-bit).</p> 2545<table> 2546 <tr> 2547 <th></th> 2548 <th>SD (Low quality)</th> 2549 <th>SD (High quality)</th> 2550 <th>HD 720p<sup>1</sup></th> 2551 <th>HD 1080p<sup>2</sup></th> 2552 <th>UHD<sup>2</sup></th> 2553 </tr> 2554 <tr> 2555 <th>Video resolution</th> 2556 <td>320 x 180 px</td> 2557 <td>640 x 360 px</td> 2558 <td>1280 x 720 px</td> 2559 <td>1920 x 1080 px</td> 2560 <td>3840 x 2160 px</td> 2561 </tr> 2562 <tr> 2563 <th>Video frame rate</th> 2564 <td>30 fps</td> 2565 <td>30 fps</td> 2566 <td>30 fps</td> 2567 <td>60 fps</td> 2568 <td>60 fps</td> 2569 </tr> 2570 <tr> 2571 <th>Video bitrate</th> 2572 <td>600 Kbps</td> 2573 <td>1.6 Mbps</td> 2574 <td>4 Mbps</td> 2575 <td>10 Mbps</td> 2576 <td>20 Mbps</td> 2577 </tr> 2578</table> 2579 2580 2581<p class="table_footnote">1 Required for Android Television device 2582implementations, but for other type of devices only when supported by hardware. 2583</p> 2584 2585<p class="table_footnote">2 STRONGLY RECOMMENDED for existing Android Television 2586device implementations when supported by hardware.</p> 2587 2588<p>Android device implementations, when supporting H.265 codec as described in 2589<a href="#5_1_3_video_codecs">section 5.1.3</a>, MUST support the Main Profile 2590Level 3 Main tier and the following SD video decoding profiles and SHOULD 2591support the HD decoding profiles. Android Television devices MUST support the 2592Main Profile Level 4.1 Main tier and the HD 1080p decoding profile and SHOULD 2593support Main10 Level 5 Main Tier profile and the UHD decoding profile.</p> 2594<table> 2595 <tr> 2596 <th></th> 2597 <th>SD (Low quality)</th> 2598 <th>SD (High quality)</th> 2599 <th>HD 720p<sup>1</sup></th> 2600 <th>HD 1080p<sup>1</sup></th> 2601 <th>UHD<sup>2</sup></th> 2602 </tr> 2603 <tr> 2604 <th>Video resolution</th> 2605 <td>352 x 288 px</td> 2606 <td>640 x 360 px</td> 2607 <td>1280 x 720 px</td> 2608 <td>1920 x 1080 px</td> 2609 <td>3840 x 2160 px</td> 2610 </tr> 2611 <tr> 2612 <th>Video frame rate</th> 2613 <td>30 fps</td> 2614 <td>30 fps</td> 2615 <td>30 fps</td> 2616 <td>60 fps<sup>2</sup></td> 2617 <td>60 fps</td> 2618 </tr> 2619 <tr> 2620 <th>Video bitrate</th> 2621 <td>600 Kbps </td> 2622 <td>1.6 Mbps</td> 2623 <td>4 Mbps</td> 2624 <td>10 Mbps</td> 2625 <td>20 Mbps</td> 2626 </tr> 2627</table> 2628 2629 2630<p class="table_footnote">1 Required for Android Television device 2631implementations, but for other type of devices only when supported by hardware. 2632</p> 2633 2634<p class="table_footnote">2 STRONGLY RECOMMENDED for existing Android Television 2635device implementations when supported by hardware.</p> 2636 2637<h2 id="5_4_audio_recording">5.4. Audio Recording</h2> 2638 2639 2640<p>While some of the requirements outlined in this section are stated as SHOULD 2641since Android 4.3, the Compatibility Definition for a future version is planned 2642to change these to MUST. Existing and new Android devices are <strong>STRONGLY 2643RECOMMENDED</strong> to meet these requirements, or they will not be able to 2644attain Android compatibility when upgraded to the future version.</p> 2645 2646<h3 id="5_4_1_raw_audio_capture">5.4.1. Raw Audio Capture</h3> 2647 2648 2649<p>Device implementations that declare android.hardware.microphone MUST allow 2650capture of raw audio content with the following characteristics:</p> 2651 2652<ul> 2653 <li><strong>Format</strong>: Linear PCM, 16-bit 2654 <li><strong>Sampling rates</strong>: 8000, 11025, 16000, 44100 2655 <li><strong>Channels</strong>: Mono 2656</ul> 2657 2658<p>The capture for the above sample rates MUST be done without up-sampling, and 2659any down-sampling MUST include an appropriate anti-aliasing filter.</p> 2660 2661<p>Device implementations that declare android.hardware.microphone SHOULD allow 2662capture of raw audio content with the following characteristics:</p> 2663 2664<ul> 2665 <li><strong>Format</strong>: Linear PCM, 16-bit 2666 <li><strong>Sampling rates</strong>: 22050, 48000 2667 <li><strong>Channels</strong>: Stereo 2668</ul> 2669 2670<p>If capture for the above sample rates is supported, then the capture MUST be 2671done without up-sampling at any ratio higher than 16000:22050 or 44100:48000. 2672Any up-sampling or down-sampling MUST include an appropriate anti-aliasing 2673filter.</p> 2674 2675<h3 id="5_4_2_capture_for_voice_recognition">5.4.2. Capture for Voice 2676Recognition</h3> 2677 2678 2679<p>In addition to the above recording specifications, when an application has 2680started recording an audio stream using the 2681android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION audio source:</p> 2682 2683<ul> 2684 <li>The device SHOULD exhibit approximately flat amplitude versus frequency 2685 characteristics: specifically, ±3 dB, from 100 Hz to 4000 Hz.</li> 2686 <li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level 2687 (SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.</li> 2688 <li>PCM amplitude levels SHOULD linearly track input SPL changes over at least 2689 a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.</li> 2690 <li>Total harmonic distortion SHOULD be less than 1% for 1 kHz at 90 dB SPL 2691 input level at the microphone.</li> 2692 <li>Noise reduction processing, if present, MUST be disabled.</li> 2693 <li>Automatic gain control, if present, MUST be disabled.</li> 2694</ul> 2695 2696<p>If the platform supports noise suppression technologies tuned for speech 2697recognition, the effect MUST be controllable from the 2698android.media.audiofx.NoiseSuppressor API. Moreover, the UUID field for the 2699noise suppressor’s effect descriptor MUST uniquely identify each 2700implementation of the noise suppression technology.</p> 2701 2702<h3 id="5_4_3_capture_for_rerouting_of_playback">5.4.3. Capture for Rerouting of 2703Playback</h3> 2704 2705 2706<p>The android.media.MediaRecorder.AudioSource class includes the REMOTE_SUBMIX 2707audio source. Devices that declare android.hardware.audio.output MUST properly 2708implement the REMOTE_SUBMIX audio source so that when an application uses the 2709android.media.AudioRecord API to record from this audio source, it can capture 2710a mix of all audio streams except for the following:</p> 2711 2712<ul> 2713 <li>STREAM_RING 2714 <li>STREAM_ALARM 2715 <li>STREAM_NOTIFICATION 2716</ul> 2717 2718<h2 id="5_5_audio_playback">5.5. Audio Playback</h2> 2719 2720 2721<p>Device implementations that declare android.hardware.audio.output MUST 2722conform to the requirements in this section.</p> 2723 2724<h3 id="5_5_1_raw_audio_playback">5.5.1. Raw Audio Playback</h3> 2725 2726 2727<p>The device MUST allow playback of raw audio content with the following 2728characteristics:</p> 2729 2730<ul> 2731 <li><strong>Format</strong>: Linear PCM, 16-bit</li> 2732 <li><strong>Sampling rates</strong>: 8000, 11025, 16000, 22050, 32000, 2733 44100</li> 2734 <li><strong>Channels</strong>: Mono, Stereo</li> 2735</ul> 2736 2737<p>The device SHOULD allow playback of raw audio content with the following 2738characteristics:</p> 2739 2740<ul> 2741 <li><strong>Sampling rates</strong>: 24000, 48000</li> 2742</ul> 2743 2744<h3 id="5_5_2_audio_effects">5.5.2. Audio Effects</h3> 2745 2746 2747<p>Android provides an 2748<a href="http://developer.android.com/reference/android/media/audiofx/AudioEffect.html">API 2749for audio effects</a> for device implementations. Device implementations that 2750declare the feature android.hardware.audio.output:</p> 2751 2752<ul> 2753 <li>MUST support the EFFECT_TYPE_EQUALIZER and EFFECT_TYPE_LOUDNESS_ENHANCER 2754 implementations controllable through the AudioEffect subclasses Equalizer, 2755 LoudnessEnhancer.</li> 2756 <li>MUST support the visualizer API implementation, controllable through the 2757 Visualizer class.</li> 2758 <li>SHOULD support the EFFECT_TYPE_BASS_BOOST, EFFECT_TYPE_ENV_REVERB, 2759 EFFECT_TYPE_PRESET_REVERB, and EFFECT_TYPE_VIRTUALIZER implementations 2760 controllable through the AudioEffect sub-classes BassBoost, 2761 EnvironmentalReverb, PresetReverb, and Virtualizer.</li> 2762</ul> 2763 2764<h3 id="5_5_3_audio_output_volume">5.5.3. Audio Output Volume</h3> 2765 2766 2767<p>Android Television device implementations MUST include support for system 2768Master Volume and digital audio output volume attenuation on supported outputs, 2769except for compressed audio passthrough output (where no audio decoding is done 2770on the device).</p> 2771 2772<h2 id="5_6_audio_latency">5.6. Audio Latency</h2> 2773 2774 2775<p>Audio latency is the time delay as an audio signal passes through a system. 2776Many classes of applications rely on short latencies, to achieve real-time 2777sound effects.</p> 2778 2779<p>For the purposes of this section, use the following definitions:</p> 2780 2781<ul> 2782 <li><strong>output latency</strong>. The interval between when an application 2783 writes a frame of PCM-coded data and when the corresponding sound can be heard 2784 by an external listener or observed by a transducer.</li> 2785 <li><strong>cold output latency</strong>. The output latency for the first 2786 frame, when the audio output system has been idle and powered down prior to 2787 the request.</li> 2788 <li><strong>continuous output latency</strong>. The output latency for 2789 subsequent frames, after the device is playing audio.</li> 2790 <li><strong>input latency</strong>. The interval between when an external 2791 sound is presented to the device and when an application reads the 2792 corresponding frame of PCM-coded data.</li> 2793 <li><strong>cold input latency</strong>. The sum of lost input time and the 2794 input latency for the first frame, when the audio input system has been idle 2795 and powered down prior to the request.</li> 2796 <li><strong>continuous input latency</strong>. The input latency for 2797 subsequent frames, while the device is capturing audio.</li> 2798 <li><strong>cold output jitter</strong>. The variance among separate 2799 measurements of cold output latency values.</li> 2800 <li><strong>cold input jitter</strong>. The variance among separate 2801 measurements of cold input latency values.</li> 2802 <li><strong>continuous round-trip latency</strong>. The sum of continuous 2803 input latency plus continuous output latency plus one buffer period. The 2804 buffer period term allows processing time for the app and for the app to 2805 mitigate phase difference between input and output streams.</li> 2806 <li><strong>OpenSL ES PCM buffer queue API</strong>. The set of PCM-related 2807 OpenSL ES APIs within Android NDK; see NDK_root/docs/opensles/index.html.</li> 2808</ul> 2809 2810<p>Device implementations that declare android.hardware.audio.output are 2811STRONGLY RECOMMENDED to meet or exceed these audio output requirements:</p> 2812 2813<ul> 2814 <li>cold output latency of 100 milliseconds or less</li> 2815 <li>continuous output latency of 45 milliseconds or less</li> 2816 <li>minimize the cold output jitter</li> 2817</ul> 2818 2819<p>If a device implementation meets the requirements of this section after any 2820initial calibration when using the OpenSL ES PCM buffer queue API, for 2821continuous output latency and cold output latency over at least one supported 2822audio output device, it is STRONGLY RECOMMENDED to report support for 2823low-latency audio, by reporting the feature android.hardware.audio.low_latency 2824via the 2825<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">android.content.pm.PackageManager</a> 2826class. Conversely, if the device implementation does not meet these requirements 2827it MUST NOT report support for low-latency audio.</p> 2828 2829<p>Device implementations that include android.hardware.microphone are STRONGLY 2830RECOMMENDED to meet these input audio requirements:</p> 2831 2832<ul> 2833 <li>cold input latency of 100 milliseconds or less</li> 2834 <li>continuous input latency of 30 milliseconds or less</li> 2835 <li>continuous round-trip latency of 50 milliseconds or less</li> 2836 <li>minimize the cold input jitter</li> 2837</ul> 2838 2839<h2 id="5_7_network_protocols">5.7. Network Protocols</h2> 2840 2841 2842<p>Devices MUST support the 2843<a href="http://developer.android.com/guide/appendix/media-formats.html">media 2844network protocols</a> for audio and video playback as specified in the Android 2845SDK documentation. Specifically, devices MUST support the following media 2846network protocols:</p> 2847 2848<ul> 2849 <li>RTSP (RTP, SDP)</li> 2850 <li>HTTP(S) progressive streaming</li> 2851 <li>HTTP(S) 2852 <a href="http://tools.ietf.org/html/draft-pantos-http-live-streaming-03">Live 2853 Streaming draft protocol, Version 3</a></li> 2854</ul> 2855 2856<h2 id="5_8_secure_media">5.8. Secure Media</h2> 2857 2858 2859<p>Device implementations that support secure video output and are capable of 2860supporting secure surfaces MUST declare support for Display.FLAG_SECURE. Device 2861implementations that declare support for Display.FLAG_SECURE, if they support a 2862wireless display protocol, MUST secure the link with a cryptographically strong 2863mechanism such as HDCP 2.x or higher for Miracast wireless displays. Similarly 2864if they support a wired external display, the device implementations MUST 2865support HDCP 1.2 or higher. Android Television device implementations MUST 2866support HDCP 2.2 for devices supporting 4K resolution and HDCP 1.4 or above for 2867lower resolutions. The upstream Android open source implementation includes 2868support for wireless (Miracast) and wired (HDMI) displays that satisfies this 2869requirement.</p> 2870 2871<h2 id="5_9_midi">5.9. Musical Instrument Digital Interface (MIDI)</h2> 2872 2873<p>If a device implementation supports the inter-app MIDI software transport 2874(virtual MIDI devices), and it supports MIDI over <em>all</em> of the following 2875MIDI-capable hardware transports for which it provides generic non-MIDI 2876connectivity, it is STRONGLY RECOMMENDED to report support for feature 2877android.software.midi via the 2878<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">android.content.pm.PackageManager</a> 2879class.</p> 2880 2881<p>The MIDI-capable hardware transports are:</p> 2882<ul> 2883 <li>USB host mode (section 7.7 USB)</li> 2884 <li>USB peripheral mode (section 7.7 USB)</li> 2885</ul> 2886 2887<p>Conversely, if the device implementation provides generic non-MIDI 2888connectivity over a particular MIDI-capable hardware transport listed above, but 2889does not support MIDI over that hardware transport, it MUST NOT report support 2890for feature android.software.midi.</p> 2891 2892<p>MIDI over Bluetooth LE acting in central role (section 7.4.3 Bluetooth) is in 2893trial use status. A device implementation that reports 2894feature android.software.midi, and which provides generic non-MIDI connectivity 2895over Bluetooth LE, SHOULD support MIDI over Bluetooth LE.</p> 2896 2897<h2 id="5_10_pro_audio">5.10. Professional Audio</h2> 2898 2899<p>If a device implementation meets <em>all</em> of the following requirements, 2900it is STRONGLY RECOMMENDED to report support for feature 2901android.hardware.audio.pro via the 2902<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">android.content.pm.PackageManager</a> 2903class.</p> 2904 2905<ul> 2906 <li>The device implementation MUST report support for feature 2907 android.hardware.audio.low_latency.</li> 2908 <li>The continuous round-trip audio latency, as defined in section 5.6 Audio 2909 Latency, MUST be 20 milliseconds or less and SHOULD be 10 milliseconds or less 2910 over at least one supported path.</li> 2911 <li>If the device includes a 4 conductor 3.5mm audio jack, the continuous 2912 round-trip audio latency MUST be 20 milliseconds or less over the audio jack 2913 path, and SHOULD be 10 milliseconds or less over at the audio jack path.</li> 2914 <li>The device implementation MUST include a USB port(s) supporting USB host 2915 mode and USB peripheral mode.</li> 2916 <li>The USB host mode MUST implement the USB audio class.</li> 2917 <li>If the device includes an HDMI port, the device implementation MUST 2918 support output in stereo and eight channels at 20-bit or 24-bit depth and 192 2919 kHz without bit-depth loss or resampling.</li> 2920 <li>The device implementation MUST report support for feature 2921 android.software.midi.</li> 2922 <li>If the device includes a 4 conductor 3.5mm audio jack, the device 2923 implementation is STRONGLY RECOMMENDED to comply with section 2924 <a href="https://source.android.com/accessories/headset/specification.html#mobile_device_jack_specifications">Mobile 2925 device (jack) specifications</a> of the 2926 <a href="https://source.android.com/accessories/headset/specification.html">Wired 2927 Audio Headset Specification (v1.1)</a>.</li> 2928</ul> 2929 2930<h1 id="6_developer_tools_and_options_compatibility">6. Developer Tools and 2931Options Compatibility</h1> 2932 2933<h2 id="6_1_developer_tools">6.1. Developer Tools</h2> 2934 2935<p>Device implementations MUST support the Android Developer Tools provided in 2936the Android SDK. Android compatible devices MUST be compatible with:</p> 2937 2938<ul> 2939 <li><a href="http://developer.android.com/tools/help/adb.html"><strong>Android 2940 Debug Bridge (adb)</strong></a> 2941 <ul> 2942 <li>Device implementations MUST support all adb functions as documented in 2943 the Android SDK including 2944 <a href="https://source.android.com/devices/input/diagnostics.html">dumpsys</a>. 2945 </li> 2946 <li>The device-side adb daemon MUST be inactive by default and there MUST be 2947 a user-accessible mechanism to turn on the Android Debug Bridge. If a device 2948 implementation omits USB peripheral mode, it MUST implement the Android 2949 Debug Bridge via local-area network (such as Ethernet or 802.11).</li> 2950 <li>Android includes support for secure adb. Secure adb enables adb on known 2951 authenticated hosts. Device implementations MUST support secure adb.</li> 2952 </ul></li> 2953 <li><a href="http://developer.android.com/tools/debugging/ddms.html"><strong>Dalvik 2954 Debug Monitor Service (ddms)</strong></a> 2955 <ul> 2956 <li>Device implementations MUST support all ddms features as documented in 2957 the Android SDK.</li> 2958 <li>As ddms uses adb, support for ddms SHOULD be inactive by default, but 2959 MUST be supported whenever the user has activated the Android Debug Bridge, 2960 as above.</li> 2961 </ul></li> 2962 <li><a href="http://developer.android.com/tools/help/monkey.html"><strong>Monkey</strong></a>. 2963 Device implementations MUST include the Monkey framework, and make it 2964 available for applications to use.</li> 2965 <li><a href="http://developer.android.com/tools/help/systrace.html"><strong>SysTrace</strong></a> 2966 <ul> 2967 <li>Device implementations MUST support systrace tool as documented in the 2968 Android SDK. Systrace must be inactive by default, and there MUST be a 2969 user-accessible mechanism to turn on Systrace.</li> 2970 <li>Most Linux-based systems and Apple Macintosh systems recognize Android 2971 devices using the standard Android SDK tools, without additional support; 2972 however Microsoft Windows systems typically require a driver for new Android 2973 devices. (For instance, new vendor IDs and sometimes new device IDs require 2974 custom USB drivers for Windows systems.)</li> 2975 <li>If a device implementation is unrecognized by the adb tool as provided 2976 in the standard Android SDK, device implementers MUST provide Windows 2977 drivers allowing developers to connect to the device using the adb protocol. 2978 These drivers MUST be provided for Windows XP, Windows Vista, Windows 7, 2979 Windows 8, and Windows 10 in both 32-bit and 64-bit versions.</li> 2980 </ul></li> 2981</ul> 2982 2983<h2 id="6_2_developer_options">6.2. Developer Options</h2> 2984 2985 2986<p>Android includes support for developers to configure application 2987development-related settings. Device implementations MUST honor the 2988<a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS">android.settings.APPLICATION_DEVELOPMENT_SETTINGS</a> 2989intent to show application development-related settings The upstream Android 2990implementation hides the Developer Options menu by default and enables users to 2991launch Developer Options after pressing seven (7) times on the 2992<strong>Settings</strong> > <strong>About Device</strong> > <strong>Build 2993Number</strong> menu item. Device implementations MUST provide a consistent 2994experience for Developer Options. Specifically, device implementations MUST hide 2995Developer Options by default and MUST provide a mechanism to enable Developer 2996Options that is consistent with the upstream Android implementation.</p> 2997 2998<h1 id="7_hardware_compatibility">7. Hardware Compatibility</h1> 2999 3000 3001<p>If a device includes a particular hardware component that has a corresponding 3002API for third-party developers, the device implementation MUST implement that 3003API as described in the Android SDK documentation. If an API in the SDK 3004interacts with a hardware component that is stated to be optional and the 3005device implementation does not possess that component:</p> 3006 3007<ul> 3008 <li>Complete class definitions (as documented by the SDK) for the component 3009 APIs MUST still be presented.</li> 3010 <li>The API’s behaviors MUST be implemented as no-ops in some reasonable 3011 fashion.</li> 3012 <li>API methods MUST return null values where permitted by the SDK 3013 documentation.</li> 3014 <li>API methods MUST return no-op implementations of classes where null values 3015 are not permitted by the SDK documentation.</li> 3016 <li>API methods MUST NOT throw exceptions not documented by the SDK 3017 documentation.</li> 3018</ul> 3019 3020<p>A typical example of a scenario where these requirements apply is the 3021telephony API: Even on non-phone devices, these APIs must be implemented as 3022reasonable no-ops.</p> 3023 3024<p>Device implementations MUST consistently report accurate hardware 3025configuration information via the getSystemAvailableFeatures() and 3026hasSystemFeature(String) methods on the 3027<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">android.content.pm.PackageManager</a> 3028class for the same build fingerprint.</p> 3029 3030<h2 id="7_1_display_and_graphics">7.1. Display and Graphics</h2> 3031 3032 3033<p>Android includes facilities that automatically adjust application assets and 3034UI layouts appropriately for the device to ensure that third-party applications 3035run well on a 3036<a href="http://developer.android.com/guide/practices/screens_support.html">variety 3037of hardware configurations</a>. Devices MUST properly implement these APIs and 3038behaviors, as detailed in this section.</p> 3039 3040<p>The units referenced by the requirements in this section are defined as 3041follows:</p> 3042 3043<ul> 3044 <li><strong>physical diagonal size</strong>. The distance in inches between 3045 two opposing corners of the illuminated portion of the display.</li> 3046 <li><strong>dots per inch (dpi)</strong>. The number of pixels encompassed by 3047 a linear horizontal or vertical span of 1”. Where dpi values are listed, 3048 both horizontal and vertical dpi must fall within the range.</li> 3049 <li><strong>aspect ratio</strong>. The ratio of the pixels of the longer 3050 dimension to the shorter dimension of the screen. For example, a display of 3051 480x854 pixels would be 854/480 = 1.779, or roughly “16:9”.</li> 3052 <li><strong>density-independent pixel (dp)</strong>. The virtual pixel unit 3053 normalized to a 160 dpi screen, calculated as: pixels = dps * (density/160). 3054 </li> 3055</ul> 3056 3057<h3 id="7_1_1_screen_configuration">7.1.1. Screen Configuration</h3> 3058 3059 3060<h4 id="7_1_1_1_screen_size">7.1.1.1. Screen Size</h4> 3061 3062<div class="note"> 3063<p>Android Watch devices (detailed in <a href="#2_device_types">section 2</a>) 3064MAY have smaller screen sizes as described in this section.</p> 3065</div> 3066 3067<p>The Android UI framework supports a variety of different screen sizes, and 3068allows applications to query the device screen size (aka “screen layout") 3069via android.content.res.Configuration.screenLayout with the 3070SCREENLAYOUT_SIZE_MASK. Device implementations MUST report the correct 3071<a href="http://developer.android.com/guide/practices/screens_support.html">screen 3072size</a> as defined in the Android SDK documentation and determined by the 3073upstream Android platform. Specifically, device implementations MUST report the 3074correct screen size according to the following logical density-independent pixel 3075(dp) screen dimensions.</p> 3076 3077<ul> 3078 <li>Devices MUST have screen sizes of at least 426 dp x 320 dp 3079 (‘small’), unless it is an Android Watch device.</li> 3080 <li>Devices that report screen size ‘normal’ MUST have screen 3081 sizes of at least 480 dp x 320 dp.</li> 3082 <li>Devices that report screen size ‘large’ MUST have screen sizes 3083 of at least 640 dp x 480 dp.</li> 3084 <li>Devices that report screen size ‘xlarge’ MUST have screen 3085 sizes of at least 960 dp x 720 dp.</li> 3086</ul> 3087 3088<p>In addition:</p> 3089 3090<ul> 3091 <li>Android Watch devices MUST have a screen with the physical diagonal size 3092 in the range from 1.1 to 2.5 inches.</li> 3093 <li>Other types of Android device implementations, with a physically 3094 integrated screen, MUST have a screen at least 2.5 inches in physical diagonal 3095 size.</li> 3096</ul> 3097 3098<p>Devices MUST NOT change their reported screen size at any time.</p> 3099 3100<p>Applications optionally indicate which screen sizes they support via the 3101<supports-screens> attribute in the AndroidManifest.xml file. Device 3102implementations MUST correctly honor applications' stated support for small, 3103normal, large, and xlarge screens, as described in the Android SDK 3104documentation.</p> 3105 3106<h4 id="7_1_1_2_screen_aspect_ratio">7.1.1.2. Screen Aspect Ratio</h4> 3107 3108<div class="note"> 3109<p>Android Watch devices MAY have an aspect ratio of 1.0 (1:1).</p> 3110</div> 3111 3112 3113<p>The screen aspect ratio MUST be a value from 1.3333 (4:3) to 1.86 (roughly 311416:9), but Android Watch devices MAY have an aspect ratio of 1.0 (1:1) because 3115such a device implementation will use a UI_MODE_TYPE_WATCH as the 3116android.content.res.Configuration.uiMode.</p> 3117 3118<h4 id="7_1_1_3_screen_density">7.1.1.3. Screen Density</h4> 3119 3120 3121<p>The Android UI framework defines a set of standard logical densities to help 3122application developers target application resources. Device implementations 3123MUST report only one of the following logical Android framework densities 3124through the android.util.DisplayMetrics APIs, and MUST execute applications at 3125this standard density and MUST NOT change the value at at any time for the 3126default display.</p> 3127 3128<ul> 3129 <li>120 dpi (ldpi)</li> 3130 <li>160 dpi (mdpi)</li> 3131 <li>213 dpi (tvdpi)</li> 3132 <li>240 dpi (hdpi)</li> 3133 <li>280 dpi (280dpi)</li> 3134 <li>320 dpi (xhdpi)</li> 3135 <li>360 dpi (360dpi)</li> 3136 <li>400 dpi (400dpi)</li> 3137 <li>420 dpi (420dpi)</li> 3138 <li>480 dpi (xxhdpi)</li> 3139 <li>560 dpi (560dpi)</li> 3140 <li>640 dpi (xxxhdpi)</li> 3141</ul> 3142 3143<p>Device implementations SHOULD define the standard Android framework density 3144that is numerically closest to the physical density of the screen, unless that 3145logical density pushes the reported screen size below the minimum supported. If 3146the standard Android framework density that is numerically closest to the 3147physical density results in a screen size that is smaller than the smallest 3148supported compatible screen size (320 dp width), device implementations SHOULD 3149report the next lowest standard Android framework density.</p> 3150 3151<h3 id="7_1_2_display_metrics">7.1.2. Display Metrics</h3> 3152 3153 3154<p>Device implementations MUST report correct values for all display metrics 3155defined in 3156<a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">android.util.DisplayMetrics</a> 3157and MUST report the same values regardless of whether the embedded or external 3158screen is used as the default display.</p> 3159 3160<h3 id="7_1_3_screen_orientation">7.1.3. Screen Orientation</h3> 3161 3162 3163<p>Devices MUST report which screen orientations they support 3164(android.hardware.screen.portrait and/or android.hardware.screen.landscape) and 3165MUST report at least one supported orientation. For example, a device with a 3166fixed orientation landscape screen, such as a television or laptop, SHOULD only 3167report android.hardware.screen.landscape.</p> 3168 3169<p>Devices that report both screen orientations MUST support dynamic orientation 3170by applications to either portrait or landscape screen orientation. That is, 3171the device must respect the application’s request for a specific screen 3172orientation. Device implementations MAY select either portrait or landscape 3173orientation as the default.</p> 3174 3175<p>Devices MUST report the correct value for the device’s current 3176orientation, whenever queried via the 3177android.content.res.Configuration.orientation, 3178android.view.Display.getOrientation(), or other APIs.</p> 3179 3180<p>Devices MUST NOT change the reported screen size or density when changing 3181orientation.</p> 3182 3183<h3 id="7_1_4_2d_and_3d_graphics_acceleration">7.1.4. 2D and 3D Graphics 3184Acceleration</h3> 3185 3186 3187<p>Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied 3188and detailed in the Android SDK documentations. Device implementations SHOULD 3189support OpenGL ES 3.0 or 3.1 on devices capable of supporting it. Device 3190implementations MUST also support 3191<a href="http://developer.android.com/guide/topics/renderscript/">Android 3192RenderScript</a>, as detailed in the Android SDK documentation.</p> 3193 3194<p>Device implementations MUST also correctly identify themselves as supporting 3195OpenGL ES 1.0, OpenGL ES 2.0, OpenGL ES 3.0 or OpenGL 3.1. That is:</p> 3196 3197<ul> 3198 <li>The managed APIs (such as via the GLES10.getString() method) MUST report 3199 support for OpenGL ES 1.0 and OpenGL ES 2.0.</li> 3200 <li>The native C/C++ OpenGL APIs (APIs available to apps via libGLES_v1CM.so, 3201 libGLES_v2.so, or libEGL.so) MUST report support for OpenGL ES 1.0 and OpenGL 3202 ES 2.0.</li> 3203 <li>Device implementations that declare support for OpenGL ES 3.0 or 3.1 MUST 3204 support the corresponding managed APIs and include support for native C/C++ 3205 APIs. On device implementations that declare support for OpenGL ES 3.0 or 3.1, 3206 libGLESv2.so MUST export the corresponding function symbols in addition to the 3207 OpenGL ES 2.0 function symbols.</li> 3208</ul> 3209 3210<p>In addition to OpenGL ES 3.1, Android provides an 3211<a href="https://developer.android.com/reference/android/opengl/GLES31Ext.html">extension 3212pack</a> with Java interfaces and native support for advanced graphics 3213functionality such as tessellation and the ASTC texture compression format. 3214Android device implementations MAY support this extension pack, and—only 3215if fully implemented—MUST identify the support through the 3216android.hardware.opengles.aep feature flag.</p> 3217 3218<p>Also, device implementations MAY implement any desired OpenGL ES extensions. 3219However, device implementations MUST report via the OpenGL ES managed and 3220native APIs all extension strings that they do support, and conversely MUST NOT 3221report extension strings that they do not support.</p> 3222 3223<p>Note that Android includes support for applications to optionally specify 3224that they require specific OpenGL texture compression formats. These formats are 3225typically vendor-specific. Device implementations are not required by Android 3226to implement any specific texture compression format. However, they SHOULD 3227accurately report any texture compression formats that they do support, via the 3228getString() method in the OpenGL API.</p> 3229 3230<p>Android includes a mechanism for applications to declare that they want to 3231enable hardware acceleration for 2D graphics at the Application, Activity, 3232Window, or View level through the use of a manifest tag 3233<a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">android:hardwareAccelerated</a> 3234or direct API calls.</p> 3235 3236<p>Device implementations MUST enable hardware acceleration by default, and MUST 3237disable hardware acceleration if the developer so requests by setting 3238android:hardwareAccelerated="false” or disabling hardware acceleration 3239directly through the Android View APIs.</p> 3240 3241<p>In addition, device implementations MUST exhibit behavior consistent with the 3242Android SDK documentation on 3243<a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">hardware 3244acceleration</a>.</p> 3245 3246<p>Android includes a TextureView object that lets developers directly integrate 3247hardware-accelerated OpenGL ES textures as rendering targets in a UI hierarchy. 3248Device implementations MUST support the TextureView API, and MUST exhibit 3249consistent behavior with the upstream Android implementation.</p> 3250 3251<p>Android includes support for EGL_ANDROID_RECORDABLE, an EGLConfig attribute 3252that indicates whether the EGLConfig supports rendering to an ANativeWindow 3253that records images to a video. Device implementations MUST support 3254<a href="https://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt">EGL_ANDROID_RECORDABLE</a> 3255extension.</p> 3256 3257<h3 id="7_1_5_legacy_application_compatibility_mode">7.1.5. Legacy Application 3258Compatibility Mode</h3> 3259 3260 3261<p>Android specifies a “compatibility mode” in which the framework 3262operates in a 'normal' screen size equivalent (320dp width) mode for the benefit 3263of legacy applications not developed for old versions of Android that pre-date 3264screen-size independence.</p> 3265 3266<ul> 3267 <li>Android Automotive does not support legacy compatibility mode.</li> 3268 <li>All other device implementations MUST include support for legacy 3269 application compatibility mode as implemented by the upstream Android open 3270 source code. That is, device implementations MUST NOT alter the triggers or 3271 thresholds at which compatibility mode is activated, and MUST NOT alter the 3272 behavior of the compatibility mode itself.</li> 3273</ul> 3274 3275<h3 id="7_1_6_screen_technology">7.1.6. Screen Technology</h3> 3276 3277 3278<p>The Android platform includes APIs that allow applications to render rich 3279graphics to the display. Devices MUST support all of these APIs as defined by 3280the Android SDK unless specifically allowed in this document. </p> 3281 3282<ul> 3283 <li>Devices MUST support displays capable of rendering 16-bit color graphics 3284 and SHOULD support displays capable of 24-bit color graphics.</li> 3285 <li>Devices MUST support displays capable of rendering animations.</li> 3286 <li>The display technology used MUST have a pixel aspect ratio (PAR) between 3287 0.9 and 1.15. That is, the pixel aspect ratio MUST be near square (1.0) with a 3288 10 ~ 15% tolerance.</li> 3289</ul> 3290 3291<h3 id="7_1_7_external_displays">7.1.7. Secondary Displays</h3> 3292 3293 3294<p>Android includes support for secondary display to enable media sharing 3295capabilities and developer APIs for accessing external displays. If a device 3296supports an external display either via a wired, wireless, or an embedded 3297additional display connection then the device implementation MUST implement the 3298<a href="http://developer.android.com/reference/android/hardware/display/DisplayManager.html">display 3299manager API</a> as described in the Android SDK documentation.</p> 3300 3301<h2 id="7_2_input_devices">7.2. Input Devices</h2> 3302 3303<p>Devices MUST support a touchscreen or meet the requirements listed in 7.2.2 3304for non-touch navigation.</p> 3305 3306<h3 id="7_2_1_keyboard">7.2.1. Keyboard</h3> 3307 3308<div class="note"> 3309<p>Android Watch and Android Automotive implementations MAY implement a soft 3310keyboard. All other device implementations MUST implement a soft keyboard and:</p> 3311</div> 3312 3313 3314<p>Device implementations:</p> 3315 3316<ul> 3317 <li>MUST include support for the Input Management Framework (which allows 3318 third-party developers to create Input Method Editors—i.e. soft 3319 keyboard) as detailed at 3320 <a href="http://developer.android.com">http://developer.android.com</a>.</li> 3321 <li>MUST provide at least one soft keyboard implementation (regardless of 3322 whether a hard keyboard is present) except for Android Watch devices where the 3323 screen size makes it less reasonable to have a soft keyboard.</li> 3324 <li>MAY include additional soft keyboard implementations.</li> 3325 <li>MAY include a hardware keyboard.</li> 3326 <li>MUST NOT include a hardware keyboard that does not match one of the 3327 formats specified in 3328 <a href="http://developer.android.com/reference/android/content/res/Configuration.html">android.content.res.Configuration.keyboard</a> 3329 (QWERTY or 12-key).</li> 3330</ul> 3331 3332<h3 id="7_2_2_non-touch_navigation">7.2.2. Non-touch Navigation</h3> 3333 3334<div class="note"> 3335<p>Android Television devices MUST support D-pad.</p> 3336</div> 3337 3338<p>Device implementations:</p> 3339 3340<ul> 3341 <li>MAY omit a non-touch navigation option (trackball, d-pad, or wheel) if the 3342 device implementation is not an Android Television device.</li> 3343 <li>MUST report the correct value for 3344 <a href="http://developer.android.com/reference/android/content/res/Configuration.html">android.content.res.Configuration.navigation</a>. 3345 </li> 3346 <li>MUST provide a reasonable alternative user interface mechanism for the 3347 selection and editing of text, compatible with Input Management Engines. The 3348 upstream Android open source implementation includes a selection mechanism 3349 suitable for use with devices that lack non-touch navigation inputs.</li> 3350</ul> 3351 3352<h3 id="7_2_3_navigation_keys">7.2.3. Navigation Keys</h3> 3353 3354<div class="note"> 3355<p>The availability and visibility requirement of the Home, Recents, and Back 3356functions differ between device types as described in this section.</p> 3357</div> 3358 3359<p>The Home, Recents, and Back functions (mapped to the key events KEYCODE_HOME, 3360KEYCODE_APP_SWITCH, KEYCODE_BACK, respectively) are essential to the Android 3361navigation paradigm and therefore:</p> 3362 3363<ul> 3364 <li>Android Handheld device implementations MUST provide the Home, Recents, 3365 and Back functions.</li> 3366 <li>Android Television device implementations MUST provide the Home and Back 3367 functions.</li> 3368 <li>Android Watch device implementations MUST have the Home function available 3369 to the user, and the Back function except for when it is in 3370 UI_MODE_TYPE_WATCH.</li> 3371 <li>Android Automotive implementations MUST provide the Home function and MAY 3372 provide Back and Recent functions.</li> 3373 <li>All other types of device implementations MUST provide the Home and Back 3374 functions.</li> 3375</ul> 3376 3377<p>These functions MAY be implemented via dedicated physical buttons (such as 3378mechanical or capacitive touch buttons), or MAY be implemented using dedicated 3379software keys on a distinct portion of the screen, gestures, touch panel, etc. 3380Android supports both implementations. All of these functions MUST be 3381accessible with a single action (e.g. tap, double-click or gesture) when 3382visible.</p> 3383 3384<p>Recents function, if provided, MUST have a visible button or icon unless 3385hidden together with other navigation functions in full-screen mode. This does 3386not apply to devices upgrading from earlier Android versions that have physical 3387buttons for navigation and no recents key.</p> 3388 3389<p>The Home and Back functions, if provided, MUST each have a visible button or 3390icon unless hidden together with other navigation functions in full-screen mode 3391or when the uiMode UI_MODE_TYPE_MASK is set to UI_MODE_TYPE_WATCH.</p> 3392 3393<p>The Menu function is deprecated in favor of action bar since Android 4.0. 3394Therefore the new device implementations shipping with Android ANDROID_VERSION 3395and later MUST NOT implement a dedicated physical button for the Menu function. 3396Older device implementations SHOULD NOT implement a dedicated physical button 3397for the Menu function, but if the physical Menu button is implemented and the 3398device is running applications with targetSdkVersion > 10, the device 3399implementation:</p> 3400 3401<ul> 3402 <li>MUST display the action overflow button on the action bar when it is 3403 visible and the resulting action overflow menu popup is not empty. For a 3404 device implementation launched before Android 4.4 but upgrading to Android 3405 ANDROID_VERSION, this is RECOMMENDED.</li> 3406 <li>MUST NOT modify the position of the action overflow popup displayed by 3407 selecting the overflow button in the action bar.</li> 3408 <li>MAY render the action overflow popup at a modified position on the screen 3409 when it is displayed by selecting the physical menu button.</li> 3410</ul> 3411 3412<p>For backwards compatibility, device implementations MUST make the Menu 3413function available to applications when targetSdkVersion is less than 10, either 3414by a physical button, a software key, or gestures. This Menu function should be 3415presented unless hidden together with other navigation functions.</p> 3416 3417<p>Android device implementations with the support of the 3418<a href="http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST">Assist 3419action</a> MUST make this accessisble with a single action (e.g. tap, 3420double-click, or gesture) when other navigation keys are visible, and are 3421STRONGLY RECOMMENDED to use the long-press on the Home button or software key as 3422the single action.</p> 3423 3424<p>Device implementations MAY use a distinct portion of the screen to display 3425the navigation keys, but if so, MUST meet these requirements:</p> 3426 3427<ul> 3428 <li>Device implementation navigation keys MUST use a distinct portion of the 3429 screen, not available to applications, and MUST NOT obscure or otherwise 3430 interfere with the portion of the screen available to applications.</li> 3431 <li>Device implementations MUST make available a portion of the display to 3432 applications that meets the requirements defined in 3433 <a href="#7_1_1_screen_configuration">section 7.1.1</a>.</li> 3434 <li>Device implementations MUST display the navigation keys when applications 3435 do not specify a system UI mode, or specify SYSTEM_UI_FLAG_VISIBLE.</li> 3436 <li>Device implementations MUST present the navigation keys in an unobtrusive 3437 “low profile” (eg. dimmed) mode when applications specify 3438 SYSTEM_UI_FLAG_LOW_PROFILE.</li> 3439 <li>Device implementations MUST hide the navigation keys when applications 3440 specify SYSTEM_UI_FLAG_HIDE_NAVIGATION.</li> 3441</ul> 3442 3443<h3 id="7_2_4_touchscreen_input">7.2.4. Touchscreen Input</h3> 3444 3445<div class="note"> 3446<p>Android Handhelds and Watch Devices MUST support touchscreen input.</p> 3447</div> 3448 3449 3450<p>Device implementations SHOULD have a pointer input system of some kind 3451(either mouse-like or touch). However, if a device implementation does not 3452support a pointer input system, it MUST NOT report the 3453android.hardware.touchscreen or android.hardware.faketouch feature constant. 3454Device implementations that do include a pointer input system:</p> 3455 3456<ul> 3457 <li>SHOULD support fully independently tracked pointers, if the device input 3458 system supports multiple pointers.</li> 3459 <li>MUST report the value of 3460 <a href="http://developer.android.com/reference/android/content/res/Configuration.html">android.content.res.Configuration.touchscreen</a> 3461 corresponding to the type of the specific touchscreen on the device.</li> 3462</ul> 3463 3464<p>Android includes support for a variety of touchscreens, touch pads, and fake 3465touch input devices. 3466<a href="http://source.android.com/devices/tech/input/touch-devices.html">Touchscreen 3467based device implementations</a> are associated with a display such that the 3468user has the impression of directly manipulating items on screen. Since the user 3469is directly touching the screen, the system does not require any additional 3470affordances to indicate the objects being manipulated. In contrast, a fake touch 3471interface provides a user input system that approximates a subset of touchscreen 3472capabilities. For example, a mouse or remote control that drives an on-screen 3473cursor approximates touch, but requires the user to first point or focus then 3474click. Numerous input devices like the mouse, trackpad, gyro-based air mouse, 3475gyro-pointer, joystick, and multi-touch trackpad can support fake touch 3476interactions. Android includes the feature constant android.hardware.faketouch, 3477which corresponds to a high-fidelity non-touch (pointer-based) input device such 3478as a mouse or trackpad that can adequately emulate touch-based input (including 3479basic gesture support), and indicates that the device supports an emulated 3480subset of touchscreen functionality. Device implementations that declare the 3481fake touch feature MUST meet the fake touch requirements in 3482<a href="#7_2_5_fake_touch_input">section 7.2.5</a>.</p> 3483 3484<p>Device implementations MUST report the correct feature corresponding to the 3485type of input used. Device implementations that include a touchscreen 3486(single-touch or better) MUST report the platform feature constant 3487android.hardware.touchscreen. Device implementations that report the platform 3488feature constant android.hardware.touchscreen MUST also report the platform 3489feature constant android.hardware.faketouch. Device implementations that do not 3490include a touchscreen (and rely on a pointer device only) MUST NOT report any 3491touchscreen feature, and MUST report only android.hardware.faketouch if they 3492meet the fake touch requirements in <a href="#7_2_5_fake_touch_input">section 34937.2.5</a>.</p> 3494 3495<h3 id="7_2_5_fake_touch_input">7.2.5. Fake Touch Input</h3> 3496 3497 3498<p>Device implementations that declare support for android.hardware.faketouch:</p> 3499 3500<ul> 3501 <li>MUST report the 3502 <a href="http://developer.android.com/reference/android/view/MotionEvent.html">absolute 3503 X and Y screen positions</a>of the pointer location and display a visual 3504 pointer on the screen.</li> 3505 <li>MUST report touch event with the action code that specifies the state 3506 change that occurs on the pointer 3507 <a href="http://developer.android.com/reference/android/view/MotionEvent.html">going 3508 down or up on the screen</a>.</li> 3509 <li>MUST support pointer down and up on an object on the screen, which allows 3510 users to emulate tap on an object on the screen.</li> 3511 <li>MUST support pointer down, pointer up, pointer down then pointer up in the 3512 same place on an object on the screen within a time threshold, which allows 3513 users to 3514 <a href="http://developer.android.com/reference/android/view/MotionEvent.html">emulate 3515 double tap</a> on an object on the screen.</li> 3516 <li>MUST support pointer down on an arbitrary point on the screen, pointer 3517 move to any other arbitrary point on the screen, followed by a pointer up, 3518 which allows users to emulate a touch drag.</li> 3519 <li>MUST support pointer down then allow users to quickly move the object to a 3520 different position on the screen and then pointer up on the screen, which 3521 allows users to fling an object on the screen.</li> 3522</ul> 3523 3524<p>Devices that declare support for 3525android.hardware.faketouch.multitouch.distinct MUST meet the requirements for 3526faketouch above, and MUST also support distinct tracking of two or more 3527independent pointer inputs.</p> 3528 3529<h3 id="7_2_6_game_controller_support">7.2.6. Game Controller Support</h3> 3530 3531 3532<p>Android Television device implementations MUST support button mappings for game 3533controllers as listed below. The upstream Android implementation includes 3534implementation for game controllers that satisfies this requirement. </p> 3535 3536<h4 id="7_2_6_1_button_mappings">7.2.6.1. Button Mappings</h4> 3537 3538 3539<p>Android Television device implementations MUST support the following key 3540mappings:</p> 3541<table> 3542 <tr> 3543 <th>Button</th> 3544 <th>HID Usage<sup>2</sup></th> 3545 <th>Android Button</th> 3546 </tr> 3547 <tr> 3548 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_A">A</a><sup>1</sup></td> 3549 <td>0x09 0x0001</td> 3550 <td>KEYCODE_BUTTON_A (96)</td> 3551 </tr> 3552 <tr> 3553 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_B">B</a><sup>1</sup></td> 3554 <td>0x09 0x0002</td> 3555 <td>KEYCODE_BUTTON_B (97)</td> 3556 </tr> 3557 <tr> 3558 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_X">X</a><sup>1</sup></td> 3559 <td>0x09 0x0004</td> 3560 <td>KEYCODE_BUTTON_X (99)</td> 3561 </tr> 3562 <tr> 3563 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_Y">Y</a><sup>1</sup></td> 3564 <td>0x09 0x0005</td> 3565 <td>KEYCODE_BUTTON_Y (100)</td> 3566 </tr> 3567 <tr> 3568 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_DPAD_UP">D-pad up</a><sup>1</sup><br /> 3569 3570<a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_DPAD_DOWN">D-pad down</a><sup>1</sup></td> 3571 <td>0x01 0x0039<sup>3</sup></td> 3572 <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_HAT_Y">AXIS_HAT_Y</a><sup>4</sup></td> 3573 </tr> 3574 <tr> 3575 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_DPAD_LEFT">D-pad left</a>1<br /> 3576 3577<a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_DPAD_RIGHT">D-pad right</a><sup>1</sup></td> 3578 <td>0x01 0x0039<sup>3</sup></td> 3579 <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_HAT_X">AXIS_HAT_X</a><sup>4</sup></td> 3580 </tr> 3581 <tr> 3582 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_L1">Left shoulder button</a><sup>1</sup></td> 3583 <td>0x09 0x0007</td> 3584 <td>KEYCODE_BUTTON_L1 (102)</td> 3585 </tr> 3586 <tr> 3587 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_R1">Right shoulder button</a><sup>1</sup></td> 3588 <td>0x09 0x0008</td> 3589 <td>KEYCODE_BUTTON_R1 (103)</td> 3590 </tr> 3591 <tr> 3592 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_THUMBL">Left stick click</a><sup>1</sup></td> 3593 <td>0x09 0x000E</td> 3594 <td>KEYCODE_BUTTON_THUMBL (106)</td> 3595 </tr> 3596 <tr> 3597 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_THUMBR">Right stick click</a><sup>1</sup></td> 3598 <td>0x09 0x000F</td> 3599 <td>KEYCODE_BUTTON_THUMBR (107)</td> 3600 </tr> 3601 <tr> 3602 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_HOME">Home</a><sup>1</sup></td> 3603 <td>0x0c 0x0223</td> 3604 <td>KEYCODE_HOME (3)</td> 3605 </tr> 3606 <tr> 3607 <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BACK">Back</a><sup>1</sup></td> 3608 <td>0x0c 0x0224</td> 3609 <td>KEYCODE_BACK (4)</td> 3610 </tr> 3611</table> 3612 3613 3614<p class="table_footnote">1 <a href="http://developer.android.com/reference/android/view/KeyEvent.html">KeyEvent</a></p> 3615 3616<p class="table_footnote">2 The above HID usages must be declared within a Game pad CA (0x01 0x0005).</p> 3617 3618<p class="table_footnote">3 This usage must have a Logical Minimum of 0, a 3619Logical Maximum of 7, a Physical Minimum of 0, a Physical Maximum of 315, Units 3620in Degrees, and a Report Size of 4. The logical value is defined to be the 3621clockwise rotation away from the vertical axis; for example, a logical value of 36220 represents no rotation and the up button being pressed, while a logical value 3623of 1 represents a rotation of 45 degrees and both the up and left keys being 3624pressed.</p> 3625 3626<p class="table_footnote">4 <a href="http://developer.android.com/reference/android/view/MotionEvent.html">MotionEvent</a></p> 3627 3628<table> 3629 <tr> 3630 <th>Analog Controls<sup>1</sup></th> 3631 <th>HID Usage</th> 3632 <th>Android Button</th> 3633 </tr> 3634 <tr> 3635 <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_LTRIGGER">Left Trigger</a></td> 3636 <td>0x02 0x00C5</td> 3637 <td>AXIS_LTRIGGER </td> 3638 </tr> 3639 <tr> 3640 <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_THROTTLE">Right Trigger</a></td> 3641 <td>0x02 0x00C4</td> 3642 <td>AXIS_RTRIGGER </td> 3643 </tr> 3644 <tr> 3645 <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_Y">Left Joystick</a></td> 3646 <td>0x01 0x0030<br /> 3647 36480x01 0x0031</td> 3649 <td>AXIS_X<br /> 3650 3651AXIS_Y</td> 3652 </tr> 3653 <tr> 3654 <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_Z">Right Joystick</a></td> 3655 <td>0x01 0x0032<br /> 3656 36570x01 0x0035</td> 3658 <td>AXIS_Z<br /> 3659 3660AXIS_RZ</td> 3661 </tr> 3662</table> 3663 3664 3665<p class="table_footnote">1 <a href="http://developer.android.com/reference/android/view/MotionEvent.html">MotionEvent</a></p> 3666 3667<h3 id="7_2_7_remote_control">7.2.7. Remote Control</h3> 3668 3669 3670<p>Android Television device implementations SHOULD provide a remote control to 3671allow users to access the TV interface. The remote control MAY be a physical 3672remote or can be a software-based remote that is accessible from a mobile phone 3673or tablet. The remote control MUST meet the requirements defined below.</p> 3674 3675<ul> 3676 <li><strong>Search affordance</strong>. Device implementations MUST fire 3677 KEYCODE_SEARCH when the user invokes voice search either on the physical or 3678 software-based remote.</li> 3679 <li><strong>Navigation</strong>. All Android Television remotes MUST include 3680 <a href="http://developer.android.com/reference/android/view/KeyEvent.html">Back, 3681 Home, and Select buttons and support for D-pad events</a>.</li> 3682</ul> 3683 3684<h2 id="7_3_sensors">7.3. Sensors</h2> 3685 3686 3687<p>Android includes APIs for accessing a variety of sensor types. Devices 3688implementations generally MAY omit these sensors, as provided for in the 3689following subsections. If a device includes a particular sensor type that has a 3690corresponding API for third-party developers, the device implementation MUST 3691implement that API as described in the Android SDK documentation and the 3692Android Open Source documentation on 3693<a href="http://source.android.com/devices/sensors/">sensors</a>. For example, 3694device implementations:</p> 3695 3696<ul> 3697 <li>MUST accurately report the presence or absence of sensors per the 3698 <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">android.content.pm.PackageManager</a> 3699 class.</li> 3700 <li>MUST return an accurate list of supported sensors via the 3701 SensorManager.getSensorList() and similar methods.</li> 3702 <li>MUST behave reasonably for all other sensor APIs (for example, by 3703 returning true or false as appropriate when applications attempt to register 3704 listeners, not calling sensor listeners when the corresponding sensors are not 3705 present; etc.).</li> 3706 <li>MUST 3707 <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">report 3708 all sensor measurements</a> using the relevant International System of Units 3709 (metric) values for each sensor type as defined in the Android SDK 3710 documentation.</li> 3711 <li>SHOULD 3712 <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html#timestamp">report 3713 the event time</a> in nanoseconds as defined in the Android SDK documentation, 3714 representing the time the event happened and synchronized with the 3715 SystemClock.elapsedRealtimeNano() clock. Existing and new Android devices are 3716 <strong>STRONGLY RECOMMENDED</strong> to meet these requirements so they will 3717 be able to upgrade to the future platform releases where this might become a 3718 REQUIRED component. The synchronization error SHOULD be below 100 3719 milliseconds.</li> 3720 <li>MUST report sensor data with a maximum latency of 100 milliseconds + 2 * 3721 sample_time for the case of a sensor streamed with a minimum required latency 3722 of 5 ms + 2 * sample_time when the application processor is active. This delay 3723 does not include any filtering delays.</li> 3724 <li>MUST report the first sensor sample within 400 milliseconds + 2 * 3725 sample_time of the sensor being activated. It is acceptable for this sample to 3726 have an accuracy of 0.</li> 3727</ul> 3728 3729<p>The list above is not comprehensive; the documented behavior of the Android 3730SDK and the Android Open Source Documentations on 3731<a href="http://source.android.com/devices/sensors/">sensors</a> is to be 3732considered authoritative.</p> 3733 3734<p>Some sensor types are composite, meaning they can be derived from data 3735provided by one or more other sensors. (Examples include the orientation sensor 3736and the linear acceleration sensor.) Device implementations SHOULD implement 3737these sensor types, when they include the prerequisite physical sensors as 3738described in 3739<a href="https://source.android.com/devices/sensors/sensor-types.html">sensor 3740types</a>. If a device implementation includes a composite sensor it MUST 3741implement the sensor as described in the Android Open Source documentation on 3742<a href="https://source.android.com/devices/sensors/sensor-types.html#composite_sensor_type_summary">composite 3743sensors</a>.</p> 3744 3745<p>Some Android sensors support a 3746<a href="https://source.android.com/devices/sensors/report-modes.html#continuous">“continuous” 3747trigger mode</a>, which returns data continuously. For any API indicated by the 3748Android SDK documentation to be a continuous sensor, device implementations MUST 3749continuously provide periodic data samples that SHOULD have a jitter below 3%, 3750where jitter is defined as the standard deviation of the difference of the 3751reported timestamp values between consecutive events.</p> 3752 3753<p>Note that the device implementations MUST ensure that the sensor event stream 3754MUST NOT prevent the device CPU from entering a suspend state or waking up from 3755a suspend state.</p> 3756 3757<p>Finally, when several sensors are activated, the power consumption SHOULD NOT 3758exceed the sum of the individual sensor’s reported power consumption.</p> 3759 3760<h3 id="7_3_1_accelerometer">7.3.1. Accelerometer</h3> 3761 3762 3763<p>Device implementations SHOULD include a 3-axis accelerometer. Android 3764Handheld devices and Android Watch devices are STRONGLY RECOMMENDED to include 3765this sensor. If a device implementation does include a 3-axis accelerometer, it: 3766</p> 3767 3768<ul> 3769 <li>MUST implement and report 3770 <a href="http://developer.android.com/reference/android/hardware/Sensor.html#TYPE_ACCELEROMETER">TYPE_ACCELEROMETER sensor</a>. 3771 </li> 3772 <li>MUST be able to report events up to a frequency of at least 50 Hz for 3773 Android Watch devices as such devices have a stricter power constraint and 3774 100 Hz for all other device types.</li> 3775 <li>SHOULD report events up to at least 200 Hz.</li> 3776 <li>MUST comply with the 3777 <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">Android 3778 sensor coordinate system</a> as detailed in the Android APIs.</li> 3779 <li>MUST be capable of measuring from freefall up to four times the gravity 3780 (4g) or more on any axis.</li> 3781 <li>MUST have a resolution of at least 12-bits and SHOULD have a resolution of 3782 at least 16-bits.</li> 3783 <li>SHOULD be calibrated while in use if the characteristics changes over the 3784 life cycle and compensated, and preserve the compensation parameters between 3785 device reboots.</li> 3786 <li>SHOULD be temperature compensated.</li> 3787 <li>MUST have a standard deviation no greater than 0.05 m/s^, where the 3788 standard deviation should be calculated on a per axis basis on samples 3789 collected over a period of at least 3 seconds at the fastest sampling rate. 3790 </li> 3791 <li>SHOULD implement the TYPE_SIGNIFICANT_MOTION, TYPE_TILT_DETECTOR, 3792 TYPE_STEP_DETECTOR, TYPE_STEP_COUNTER composite sensors as described in the 3793 Android SDK document. Existing and new Android devices are <strong>STRONGLY 3794 RECOMMENDED</strong> to implement the TYPE_SIGNIFICANT_MOTION composite 3795 sensor. If any of these sensors are implemented, the sum of their power 3796 consumption MUST always be less than 4 mW and SHOULD each be below 2 mW and 3797 0.5 mW for when the device is in a dynamic or static condition.</li> 3798 <li>If a gyroscope sensor is included, MUST implement the TYPE_GRAVITY and 3799 TYPE_LINEAR_ACCELERATION composite sensors and SHOULD implement the 3800 TYPE_GAME_ROTATION_VECTOR composite sensor. Existing and new Android devices 3801 are STRONGLY RECOMMENDED to implement the TYPE_GAME_ROTATION_VECTOR sensor. 3802 </li> 3803 <li>MUST implement a TYPE_ROTATION_VECTOR composite sensor, if a gyroscope 3804 sensor and a magnetometer sensor is also included.</li> 3805</ul> 3806 3807<h3 id="7_3_2_magnetometer">7.3.2. Magnetometer</h3> 3808 3809 3810<p>Device implementations SHOULD include a 3-axis magnetometer (compass). If a 3811device does include a 3-axis magnetometer, it:</p> 3812 3813<ul> 3814 <li>MUST implement the TYPE_MAGNETIC_FIELD sensor and SHOULD also implement 3815 TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor. Existing and new Android devices are 3816 STRONGLY RECOMMENDED to implement the TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor. 3817 </li> 3818 <li>MUST be able to report events up to a frequency of at least 10 Hz and 3819 SHOULD report events up to at least 50 Hz.</li> 3820 <li>MUST comply with the 3821 <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">Android 3822 sensor coordinate system</a> as detailed in the Android APIs.</li> 3823 <li>MUST be capable of measuring between -900 µT and +900 µT on 3824 each axis before saturating.</li> 3825 <li>MUST have a hard iron offset value less than 700 µT and SHOULD have 3826 a value below 200 µT, by placing the magnetometer far from dynamic 3827 (current-induced) and static (magnet-induced) magnetic fields.</li> 3828 <li>MUST have a resolution equal or denser than 0.6 µT and SHOULD have a 3829 resolution equal or denser than 0.2 µ.</li> 3830 <li>SHOULD be temperature compensated.</li> 3831 <li>MUST support online calibration and compensation of the hard iron bias, 3832 and preserve the compensation parameters between device reboots.</li> 3833 <li>MUST have the soft iron compensation applied—the calibration can be 3834 done either while in use or during the production of the device.</li> 3835 <li>SHOULD have a standard deviation, calculated on a per axis basis on 3836 samples collected over a period of at least 3 seconds at the fastest sampling 3837 rate, no greater than 0.5 µT.</li> 3838 <li>MUST implement a TYPE_ROTATION_VECTOR composite sensor, if an 3839 accelerometer sensor and a gyroscope sensor is also included.</li> 3840 <li>MAY implement the TYPE_GEOMAGNETIC_ROTATION_VECTOR sensor if an 3841 accelerometer sensor is also implemented. However if implemented, it MUST 3842 consume less than 10 mW and SHOULD consume less than 3 mW when the sensor is 3843 registered for batch mode at 10 Hz.</li> 3844</ul> 3845 3846<h3 id="7_3_3_gps">7.3.3. GPS</h3> 3847 3848 3849<p>Device implementations SHOULD include a GPS receiver. If a device 3850implementation does include a GPS receiver, it SHOULD include some form 3851of“assisted GPS” technique to minimize GPS lock-on time.</p> 3852 3853<h3 id="7_3_4_gyroscope">7.3.4. Gyroscope</h3> 3854 3855 3856<p>Device implementations SHOULD include a gyroscope (angular change sensor). 3857Devices SHOULD NOT include a gyroscope sensor unless a 3-axis accelerometer is 3858also included. If a device implementation includes a gyroscope, it:</p> 3859 3860<ul> 3861 <li>MUST implement the TYPE_GYROSCOPE sensor and SHOULD also implement 3862 TYPE_GYROSCOPE_UNCALIBRATED sensor. Existing and new Android devices are 3863 STRONGLY RECOMMENDED to implement the SENSOR_TYPE_GYROSCOPE_UNCALIBRATED 3864 sensor.</li> 3865 <li>MUST be capable of measuring orientation changes up to 1,000 degrees per 3866 second.</li> 3867 <li>MUST be able to report events up to a frequency of at least 50 Hz for 3868 Android Watch devices as such devices have a stricter power constraint and 100 3869 Hz for all other device types.</li> 3870 <li>SHOULD report events up to at least 200 Hz.</li> 3871 <li>MUST have a resolution of 12-bits or more and SHOULD have a resolution of 3872 16-bits or more.</li> 3873 <li>MUST be temperature compensated.</li> 3874 <li>MUST be calibrated and compensated while in use, and preserve the 3875 compensation parameters between device reboots.</li> 3876 <li>MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per 3877 Hz, or rad^2 / s). The variance is allowed to vary with the sampling rate, but 3878 must be constrained by this value. In other words, if you measure the variance 3879 of the gyro at 1 Hz sampling rate it should be no greater than 1e-7 rad^2/s^2. 3880 </li> 3881 <li>MUST implement a TYPE_ROTATION_VECTOR composite sensor, if an 3882 accelerometer sensor and a magnetometer sensor is also included.</li> 3883 <li>If an accelerometer sensor is included, MUST implement the TYPE_GRAVITY 3884 and TYPE_LINEAR_ACCELERATION composite sensors and SHOULD implement the 3885 TYPE_GAME_ROTATION_VECTOR composite sensor. Existing and new Android devices 3886 are STRONGLY RECOMMENDED to implement the TYPE_GAME_ROTATION_VECTOR sensor. 3887 </li> 3888</ul> 3889 3890<h3 id="7_3_5_barometer">7.3.5. Barometer</h3> 3891 3892 3893<p>Device implementations SHOULD include a barometer (ambient air pressure 3894sensor). If a device implementation includes a barometer, it:</p> 3895 3896<ul> 3897 <li>MUST implement and report TYPE_PRESSURE sensor.</li> 3898 <li>MUST be able to deliver events at 5 Hz or greater.</li> 3899 <li>MUST have adequate precision to enable estimating altitude.</li> 3900 <li>MUST be temperature compensated.</li> 3901</ul> 3902 3903<h3 id="7_3_6_thermometer">7.3.6. Thermometer</h3> 3904 3905 3906<p>Device implementations MAY include an ambient thermometer (temperature 3907sensor). If present, it MUST be defined as SENSOR_TYPE_AMBIENT_TEMPERATURE and 3908it MUST measure the ambient (room) temperature in degrees Celsius.</p> 3909 3910<p>Device implementations MAY but SHOULD NOT include a CPU temperature sensor. 3911If present, it MUST be defined as SENSOR_TYPE_TEMPERATURE, it MUST measure the 3912temperature of the device CPU, and it MUST NOT measure any other temperature. 3913Note the SENSOR_TYPE_TEMPERATURE sensor type was deprecated in Android 4.0.</p> 3914 3915<h3 id="7_3_7_photometer">7.3.7. Photometer</h3> 3916 3917 3918<p>Device implementations MAY include a photometer (ambient light sensor).</p> 3919 3920<h3 id="7_3_8_proximity_sensor">7.3.8. Proximity Sensor</h3> 3921 3922 3923<p>Device implementations MAY include a proximity sensor. Devices that can make 3924a voice call and indicate any value other than PHONE_TYPE_NONE in getPhoneType 3925SHOULD include a proximity sensor. If a device implementation does include a 3926proximity sensor, it:</p> 3927 3928<ul> 3929 <li>MUST measure the proximity of an object in the same direction as the 3930 screen. That is, the proximity sensor MUST be oriented to detect objects close 3931 to the screen, as the primary intent of this sensor type is to detect a phone 3932 in use by the user. If a device implementation includes a proximity sensor 3933 with any other orientation, it MUST NOT be accessible through this API.</li> 3934 <li>MUST have 1-bit of accuracy or more.</li> 3935</ul> 3936 3937 3938<h3 id="7_3_9_hifi_sensors">7.3.9. High Fidelity Sensors</h3> 3939 3940<p>Device implementations supporting a set of higher quality sensors that can 3941meet all the requirements listed in this section MUST identify the support 3942through the <code>android.hardware.sensor.hifi_sensors</code> feature flag.</p> 3943 3944<p>A device declaring android.hardware.sensor.hifi_sensors MUST support all of 3945the following sensor types meeting the quality requirements as below:</p> 3946 3947<ul> 3948 <li>SENSOR_TYPE_ACCELEROMETER 3949 <ul> 3950 <li>MUST have a measurement range between at least -8g and +8g.</li> 3951 <li>MUST have a measurement resolution of at least 1024 LSB/G.</li> 3952 <li>MUST have a minimum measurement frequency of 12.5 Hz or lower.</li> 3953 <li>MUST have a maxmium measurement frequency of 200 Hz or higher.</li> 3954 <li>MUST have a measurement noise not above 400uG/√Hz.</li> 3955 <li>MUST implement a non-wake-up form of this sensor with a buffering 3956 capability of at least 3000 sensor events.</li> 3957 <li>MUST have a batching power consumption not worse than 3 mW.</li> 3958 </ul> 3959 </li> 3960 <li>SENSOR_TYPE_GYROSCOPE 3961 <ul> 3962 <li>MUST have a measurement range between at least -1000 and +1000 dps.</li> 3963 <li>MUST have a measurement resolution of at least 16 LSB/dps.</li> 3964 <li>MUST have a minimum measurement frequency of 12.5 Hz or lower.</li> 3965 <li>MUST have a maxmium measurement frequency of 200 Hz or higher.</li> 3966 <li>MUST have a measurement noise not above 0.014°/s/√Hz.</li> 3967 </ul> 3968 </li> 3969 <li>SENSOR_TYPE_GYROSCOPE_UNCALIBRATED with the same quality requirements as 3970 SENSOR_TYPE_GYROSCOPE.</li> 3971 <li>SENSOR_TYPE_GEOMAGNETIC_FIELD 3972 <ul> 3973 <li>MUST have a measurement range between at least -900 and +900 uT.</li> 3974 <li>MUST have a measurement resolution of at least 5 LSB/uT.</li> 3975 <li>MUST have a minimum measurement frequency of 5 Hz or lower.</li> 3976 <li>MUST have a maxmium measurement frequency of 50 Hz or higher.</li> 3977 <li>MUST have a measurement noise not above 0.5 uT.</li> 3978 </ul> 3979 </li> 3980 <li>SENSOR_TYPE_MAGNETIC_FIELD_UNCALIBRATED with the same quality requirements 3981 as SENSOR_TYPE_GEOMAGNETIC_FIELD and in addition: 3982 <ul> 3983 <li>MUST implement a non-wake-up form of this sensor with a buffering 3984 capability of at least 600 sensor events.</li> 3985 </ul> 3986 </li> 3987 <li>SENSOR_TYPE_PRESSURE 3988 <ul> 3989 <li>MUST have a measurement range between at least 300 and 1100 hPa.</li> 3990 <li>MUST have a measurement resolution of at least 80 LSB/hPa.</li> 3991 <li>MUST have a minimum measurement frequency of 1 Hz or lower.</li> 3992 <li>MUST have a maximum measurement frequency of 10 Hz or higher.</li> 3993 <li>MUST have a measurement noise not above 2 Pa/√Hz.</li> 3994 <li>MUST implement a non-wake-up form of this sensor with a buffering 3995 capability of at least 300 sensor events.</li> 3996 <li>MUST have a batching power consumption not worse than 2 mW.</li> 3997 </ul> 3998 </li> 3999 <li>SENSOR_TYPE_ROTATION_VECTOR 4000 <ul> 4001 <li>MUST have a batching power consumption not worse than 4 mW.</li> 4002 </ul> 4003 </li> 4004 <li>SENSOR_TYPE_GAME_ROTATION_VECTOR MUST implement a non-wake-up form of this 4005 sensor with a buffering capability of at least 300 sensor events.</li> 4006 <li>SENSOR_TYPE_SIGNIFICANT_MOTION 4007 <ul> 4008 <li>MUST have a power consumption not worse than 0.5 mW when device is 4009 static and 1.5 mW when device is moving.</li> 4010 </ul> 4011 </li> 4012 <li>SENSOR_TYPE_STEP_DETECTOR 4013 <ul> 4014 <li>MUST implement a non-wake-up form of this sensor with a buffering 4015 capability of at least 100 sensor events.</li> 4016 <li>MUST have a power consumption not worse than 0.5 mW when device is 4017 static and 1.5 mW when device is moving.</li> 4018 <li>MUST have a batching power consumption not worse than 4 mW.</li> 4019 </ul> 4020 </li> 4021 <li>SENSOR_TYPE_STEP_COUNTER 4022 <ul> 4023 <li>MUST have a power consumption not worse than 0.5 mW when device is 4024 static and 1.5 mW when device is moving.</li> 4025 </ul> 4026 </li> 4027 <li>SENSOR_TILT_DETECTOR 4028 <ul> 4029 <li>MUST have a power consumption not worse than 0.5 mW when device is 4030 static and 1.5 mW when device is moving.</li> 4031 </ul> 4032 </li> 4033</ul> 4034 4035<p>Also such a device MUST meet the following sensor subsystem requirements:</p> 4036 4037<ul> 4038 <li>The event timestamp of the same physical event reported by the 4039 Accelerometer, Gyroscope sensor and Magnetometer MUST be within 2.5 4040 milliseconds of each other.</li> 4041 <li>The Gyroscope sensor event timestamps MUST be on the same time base as the 4042 camera subsystem and within 1 millisconds of error.</li> 4043 <li>The latency of delivery of samples to the HAL SHOULD be below 5 4044 milliseconds from the instant the data is available on the physical sensor 4045 hardware.</li> 4046 <li>The power consumption MUST not be higher than 0.5 mW when device is static 4047 and 2.0 mW when device is moving when any combination of the following sensors 4048 are enabled: 4049 <ul> 4050 <li>SENSOR_TYPE_SIGNIFICANT_MOTION</li> 4051 <li>SENSOR_TYPE_STEP_DETECTOR</li> 4052 <li>SENSOR_TYPE_STEP_COUNTER</li> 4053 <li>SENSOR_TILT_DETECTORS</li> 4054 </ul> 4055 </li> 4056</ul> 4057 4058<p>Note that all power consumption requirements in this section do not include 4059the power consumption of the Application Processor. It is inclusive of the power 4060drawn by the entire sensor chain—the sensor, any supporting circuitry, any 4061dedicated sensor processing system, etc.</p> 4062 4063<p>The following sensor types MAY also be supported on a device implementation 4064declaring android.hardware.sensor.hifi_sensors, but if these sensor types are 4065present they MUST meet the following minimum buffering capability requirement: 4066</p> 4067 4068<ul> 4069 <li>SENSOR_TYPE_PROXIMITY: 100 sensor events</li> 4070</ul> 4071 4072<h3 id="7_3_10_fingeprint">7.3.10. Fingerprint Sensor</h3> 4073 4074<p>Device implementations with a secure lock screen SHOULD include a fingerprint 4075sensor. If a device implementation includes a fingerprint sensor and has a 4076corresponding API for third-party developers, it:</p> 4077 4078<ul> 4079 <li>MUST declare support for the android.hardware.fingerprint feature.</li> 4080 <li>MUST fully implement the 4081 <a href="https://developer.android.com/reference/android/hardware/fingerprint/package-summary.html">corresponding 4082 API</a> as described in the Android SDK documentation.</li> 4083 <li>MUST have a false acceptance rate not higher than 0.002%.</li> 4084 <li>Is STRONGLY RECOMMENDED to have a false rejection rate not higher than 4085 10%, and a latency from when the fingerprint sensor is touched until the 4086 screen is unlocked below 1 second, for 1 enrolled finger.</li> 4087 <li>MUST rate limit attempts for at least 30 seconds after 5 false trials for 4088 fingerprint verification.</li> 4089 <li>MUST have a hardware-backed keystore implementation, and perform the 4090 fingerprint matching in a Trusted Execution Environment (TEE) or on a chip 4091 with a secure channel to the TEE.</li> 4092 <li>MUST have all identifiable fingerprint data encrypted and 4093 cryptographically authenticated such that they cannot be acquired, read or 4094 altered outside of the Trusted Execution Environment (TEE) as documented in 4095 the 4096 <a href="https://source.android.com/devices/tech/security/authentication/fingerprint-hal.html">implementation 4097 guidelines</a> on the Android Open Source Project site.</li> 4098 <li>MUST prevent adding a fingerprint without first establishing a chain of 4099 trust by having the user confirm existing or add a new device credential 4100 (PIN/pattern/password) using the TEE as implemented in the Android Open Source 4101 project.</li> 4102 <li>MUST NOT enable 3rd-party applications to distinguish between individual 4103 fingerprints.</li> 4104 <li>MUST honor the DevicePolicyManager.KEYGUARD_DISABLE_FINGERPRINT flag.</li> 4105 <li>MUST, when upgraded from a version earlier than Android 6.0, have the 4106 fingerprint data securely migrated to meet the above requirements or removed. 4107 </li> 4108 <li>SHOULD use the Android Fingerprint icon provided in the Android Open 4109 Source Project.</li> 4110</ul> 4111 4112<h2 id="7_4_data_connectivity">7.4. Data Connectivity</h2> 4113 4114 4115<h3 id="7_4_1_telephony">7.4.1. Telephony</h3> 4116 4117 4118<p>“Telephony” as used by the Android APIs and this document refers 4119specifically to hardware related to placing voice calls and sending SMS messages 4120via a GSM or CDMA network. While these voice calls may or may not be 4121packet-switched, they are for the purposes of Android considered independent of 4122any data connectivity that may be implemented using the same network. In other 4123words, the Android “telephony” functionality and APIs refer 4124specifically to voice calls and SMS. For instance, device implementations that 4125cannot place calls or send/receive SMS messages MUST NOT report the 4126android.hardware.telephony feature or any subfeatures, regardless of whether 4127they use a cellular network for data connectivity.</p> 4128 4129<p>Android MAY be used on devices that do not include telephony hardware. That 4130is, Android is compatible with devices that are not phones. However, if a device 4131implementation does include GSM or CDMA telephony, it MUST implement full 4132support for the API for that technology. Device implementations that do not 4133include telephony hardware MUST implement the full APIs as no-ops.</p> 4134 4135<h3 id="7_4_2_ieee_802_11_wi-fi">7.4.2. IEEE 802.11 (Wi-Fi)</h3> 4136 4137<div class="note"> 4138<p>Android Television device implementations MUST include Wi-Fi support.</p> 4139</div> 4140 4141 4142<p>Android Television device implementations MUST include support for one or 4143more forms of 802.11 (b/g/a/n, etc.) and other types of Android device 4144implementation SHOULD include support for one or more forms of 802.11. If a 4145device implementation does include support for 802.11 and exposes the 4146functionality to a third-party application, it MUST implement the corresponding 4147Android API and:</p> 4148 4149<ul> 4150 <li>MUST report the hardware feature flag android.hardware.wifi.</li> 4151 <li>MUST implement the 4152 <a href="http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html">multicast 4153 API</a> as described in the SDK documentation.</li> 4154 <li>MUST support multicast DNS (mDNS) and MUST NOT filter mDNS packets 4155 (224.0.0.251) at any time of operation including: 4156 <ul> 4157 <li>Even when the screen is not in an active state.</li> 4158 <li>For Android Television device implementations, even when in standby 4159 power states.</li> 4160 </ul> 4161</ul> 4162 4163<h4 id="7_4_2_1_wi-fi_direct">7.4.2.1. Wi-Fi Direct</h4> 4164 4165 4166<p>Device implementations SHOULD include support for Wi-Fi Direct (Wi-Fi 4167peer-to-peer). If a device implementation does include support for Wi-Fi Direct, 4168it MUST implement the 4169<a href="http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html">corresponding 4170Android API</a> as described in the SDK documentation. If a device 4171implementation includes support for Wi-Fi Direct, then it:</p> 4172 4173<ul> 4174 <li>MUST report the hardware feature android.hardware.wifi.direct.</li> 4175 <li>MUST support regular Wi-Fi operation.</li> 4176 <li>SHOULD support concurrent Wi-Fi and Wi-Fi Direct operation.</li> 4177</ul> 4178 4179<h4 id="7_4_2_2_wi-fi_tunneled_direct_link_setup">7.4.2.2. Wi-Fi Tunneled Direct 4180Link Setup</h4> 4181 4182<div class="note"> 4183<p>Android Television device implementations MUST include support for Wi-Fi 4184Tunneled Direct Link Setup (TDLS).</p> 4185</div> 4186 4187 4188<p>Android Television device implementations MUST include support for 4189<a href="http://developer.android.com/reference/android/net/wifi/WifiManager.html">Wi-Fi 4190Tunneled Direct Link Setup (TDLS)</a> and other types of Android device 4191implementations SHOULD include support for Wi-Fi TDLS as described in the 4192Android SDK Documentation. If a device implementation does include support for 4193TDLS and TDLS is enabled by the WiFiManager API, the device:</p> 4194 4195<ul> 4196 <li>SHOULD use TDLS only when it is possible AND beneficial.</li> 4197 <li>SHOULD have some heuristic and NOT use TDLS when its performance might be 4198 worse than going through the Wi-Fi access point.</li> 4199</ul> 4200 4201<h3 id="7_4_3_bluetooth">7.4.3. Bluetooth</h3> 4202 4203<div class="note"> 4204<p>Android Watch and Automotive implementations MUST support Bluetooth. Android 4205Television implementations MUST support Bluetooth and Bluetooth LE.</p> 4206</div> 4207 4208 4209<p>Android includes support for 4210<a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">Bluetooth 4211and Bluetooth Low Energy </a>. Device implementations that include support for 4212Bluetooth and Bluetooth Low Energy MUST declare the relevant platform features 4213(android.hardware.bluetooth and android.hardware.bluetooth_le respectively) and 4214implement the platform APIs. Device implementations SHOULD implement relevant 4215Bluetooth profiles such as A2DP, AVCP, OBEX, etc. as appropriate for the device. 4216Android Television device implementations MUST support Bluetooth and Bluetooth 4217LE.</p> 4218 4219<p>Device implementations including support for Bluetooth Low Energy:</p> 4220 4221<ul> 4222 <li>MUST declare the hardware feature android.hardware.bluetooth_le.</li> 4223 <li>MUST enable the GATT (generic attribute profile) based Bluetooth APIs as 4224 described in the SDK documentation and 4225 <a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">android.bluetooth</a>. 4226 </li> 4227 <li>MUST implement a Resolvable Private Address (RPA) timeout no longer than 4228 15 minutes, and rotate the address at timeout to protect user privacy.</li> 4229 <li>SHOULD support offloading of the filtering logic to the bluetooth chipset 4230 when implementing the 4231 <a href="https://developer.android.com/reference/android/bluetooth/le/ScanFilter.html">ScanFilter 4232 API</a>, and MUST report the correct value of where the filtering logic is 4233 implemented whenever queried via the 4234 android.bluetooth.BluetoothAdapter.isOffloadedFilteringSupported() method. 4235 </li> 4236 <li>SHOULD support offloading of the batched scanning to the bluetooth 4237 chipset, but if not supported, MUST report ‘false’ whenever 4238 queried via the 4239 android.bluetooth.BluetoothAdapter.isOffloadedScanBatchingSupported() method. 4240 </li> 4241 <li>SHOULD support multi advertisement with at least 4 slots, but if not 4242 supported, MUST report ‘false’ whenever queried via the 4243 android.bluetooth.BluetoothAdapter.isMultipleAdvertisementSupported() method. 4244 </li> 4245</ul> 4246 4247<h3 id="7_4_4_near-field_communications">7.4.4. Near-Field Communications</h3> 4248 4249 4250<p>Device implementations SHOULD include a transceiver and related hardware for 4251Near-Field Communications (NFC). If a device implementation does include NFC 4252hardware and plans to make it available to third-party apps, then it:</p> 4253 4254<ul> 4255 <li>MUST report the android.hardware.nfc feature from the 4256 <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">android.content.pm.PackageManager.hasSystemFeature() 4257 method</a>.</li> 4258 <li>MUST be capable of reading and writing NDEF messages via the following NFC 4259 standards: 4260 <ul> 4261 <li>MUST be capable of acting as an NFC Forum reader/writer (as defined by 4262 the NFC Forum technical specification NFCForum-TS-DigitalProtocol-1.0) via 4263 the following NFC standards: 4264 <ul> 4265 <li>NfcA (ISO14443-3A)</li> 4266 <li>NfcB (ISO14443-3B)</li> 4267 <li>NfcF (JIS X 6319-4)</li> 4268 <li>IsoDep (ISO 14443-4)</li> 4269 <li>NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)</li> 4270 </ul> 4271 <li>STRONGLY RECOMMENDED to be capable of reading and writing NDEF messages as 4272 well as raw data via the following NFC standards. Note that while the NFC 4273 standards below are stated as STRONGLY RECOMMENDED, the Compatibility 4274 Definition for a future version is planned to change these to MUST. These 4275 standards are optional in this version but will be required in future 4276 versions. Existing and new devices that run this version of Android are very 4277 strongly encouraged to meet these requirements now so they will be able to 4278 upgrade to the future platform releases. 4279 <ul> 4280 <li>NfcV (ISO 15693)</li> 4281 </ul></li> 4282 <li>SHOULD be capable of reading the barcode and URL (if encoded) of 4283 <a href="http://developer.android.com/reference/android/nfc/tech/NfcBarcode.html">Thinfilm 4284 NFC Barcode</a> products.</li> 4285 <li>MUST be capable of transmitting and receiving data via the following 4286 peer-to-peer standards and protocols: 4287 <ul> 4288 <li>ISO 18092</li> 4289 <li>LLCP 1.2 (defined by the NFC Forum)</li> 4290 <li>SDP 1.0 (defined by the NFC Forum)</li> 4291 <li><a href="http://static.googleusercontent.com/media/source.android.com/en/us/compatibility/ndef-push-protocol.pdf">NDEF 4292 Push Protocol</a></li> 4293 <li>SNEP 1.0 (defined by the NFC Forum)</li> 4294 </ul></li> 4295 <li>MUST include support for <a href="http://developer.android.com/guide/topics/connectivity/nfc/nfc.html">Android Beam</a>: 4296 <ul> 4297 <li>MUST implement the SNEP default server. Valid NDEF messages received by 4298 the default SNEP server MUST be dispatched to applications using the 4299 android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam in 4300 settings MUST NOT disable dispatch of incoming NDEF message.</li> 4301 <li>MUST honor the android.settings.NFCSHARING_SETTINGS intent to show 4302 <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS">NFC 4303 sharing settings</a>.</li> 4304 <li>MUST implement the NPP server. Messages received by the NPP server MUST 4305 be processed the same way as the SNEP default server.</li> 4306 <li>MUST implement a SNEP client and attempt to send outbound P2P NDEF to 4307 the default SNEP server when Android Beam is enabled. If no default SNEP 4308 server is found then the client MUST attempt to send to an NPP server.</li> 4309 <li>MUST allow foreground activities to set the outbound P2P NDEF message 4310 using android.nfc.NfcAdapter.setNdefPushMessage, and 4311 android.nfc.NfcAdapter.setNdefPushMessageCallback, and 4312 android.nfc.NfcAdapter.enableForegroundNdefPush.</li> 4313 <li>SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam', 4314 before sending outbound P2P NDEF messages.</li> 4315 <li>SHOULD enable Android Beam by default and MUST be able to send and 4316 receive using Android Beam, even when another proprietary NFC P2p mode is 4317 turned on.</li> 4318 <li>MUST support NFC Connection handover to Bluetooth when the device 4319 supports Bluetooth Object Push Profile. Device implementations MUST support 4320 connection handover to Bluetooth when using 4321 android.nfc.NfcAdapter.setBeamPushUris, by implementing the 4322 “<a href="http://members.nfc-forum.org/specs/spec_list/#conn_handover">Connection 4323 Handover version 1.2</a>” and 4324 “<a href="http://members.nfc-forum.org/apps/group_public/download.php/18688/NFCForum-AD-BTSSP_1_1.pdf">Bluetooth 4325 Secure Simple Pairing Using NFC version 1.0</a>” specs from the NFC 4326 Forum. Such an implementation MUST implement the handover LLCP service with 4327 service name “urn:nfc:sn:handover” for exchanging the handover 4328 request/select records over NFC, and it MUST use the Bluetooth Object Push 4329 Profile for the actual Bluetooth data transfer. For legacy reasons (to 4330 remain compatible with Android 4.1 devices), the implementation SHOULD still 4331 accept SNEP GET requests for exchanging the handover request/select records 4332 over NFC. However an implementation itself SHOULD NOT send SNEP GET requests 4333 for performing connection handover.</li> 4334 </ul></li> 4335 <li>MUST poll for all supported technologies while in NFC discovery mode.</li> 4336 <li>SHOULD be in NFC discovery mode while the device is awake with the screen 4337 active and the lock-screen unlocked.</li> 4338</ul> 4339</ul> 4340 4341<p>(Note that publicly available links are not available for the JIS, ISO, and 4342NFC Forum specifications cited above.)</p> 4343 4344<p>Android includes support for NFC Host Card Emulation (HCE) mode. If a 4345device implementation does include an NFC controller chipset capable of HCE and 4346Application ID (AID) routing, then it:</p> 4347 4348<ul> 4349 <li>MUST report the android.hardware.nfc.hce feature constant.</li> 4350 <li>MUST support 4351 <a href="http://developer.android.com/guide/topics/connectivity/nfc/hce.html">NFC 4352 HCE APIs</a> as defined in the Android SDK.</li> 4353</ul> 4354 4355<p>Additionally, device implementations MAY include reader/writer support for 4356the following MIFARE technologies.</p> 4357 4358<ul> 4359 <li>MIFARE Classic</li> 4360 <li>MIFARE Ultralight</li> 4361 <li>NDEF on MIFARE Classic</li> 4362</ul> 4363 4364<p>Note that Android includes APIs for these MIFARE types. If a device 4365implementation supports MIFARE in the reader/writer role, it:</p> 4366 4367<ul> 4368 <li>MUST implement the corresponding Android APIs as documented by the Android 4369 SDK.</li> 4370 <li>MUST report the feature com.nxp.mifare from the 4371 <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">android.content.pm.PackageManager.hasSystemFeature()</a> 4372 method. Note that this is not a standard Android feature and as such does not 4373 appear as a constant in the android.content.pm.PackageManager class.</li> 4374 <li>MUST NOT implement the corresponding Android APIs nor report the 4375 com.nxp.mifare feature unless it also implements general NFC support as 4376 described in this section.</li> 4377</ul> 4378 4379<p>If a device implementation does not include NFC hardware, it MUST NOT declare 4380the android.hardware.nfc feature from the 4381<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">android.content.pm.PackageManager.hasSystemFeature()</a> 4382method, and MUST implement the Android NFC API as a no-op.</p> 4383 4384<p>As the classes android.nfc.NdefMessage and android.nfc.NdefRecord represent a 4385protocol-independent data representation format, device implementations MUST 4386implement these APIs even if they do not include support for NFC or declare the 4387android.hardware.nfc feature.</p> 4388 4389<h3 id="7_4_5_minimum_network_capability">7.4.5. Minimum Network Capability</h3> 4390 4391 4392<p>Device implementations MUST include support for one or more forms of data 4393networking. Specifically, device implementations MUST include support for at 4394least one data standard capable of 200Kbit/sec or greater. Examples of 4395technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, 4396Ethernet, Bluetooth PAN, etc.</p> 4397 4398<p>Device implementations where a physical networking standard (such as 4399Ethernet) is the primary data connection SHOULD also include support for at 4400least one common wireless data standard, such as 802.11 (Wi-Fi).</p> 4401 4402<p>Devices MAY implement more than one form of data connectivity.</p> 4403 4404<p>Devices MUST include an IPv6 networking stack and support IPv6 communication 4405using the managed APIs, such as <code>java.net.Socket</code> and 4406<code>java.net.URLConnection</code>, as well as the native APIs, such as 4407<code>AF_INET6</code> sockets. The required level of IPv6 support depends on 4408the network type, as follows:</p> 4409<ul> 4410 <li>Devices that support Wi-Fi networks MUST support dual-stack and IPv6-only 4411 operation on Wi-Fi.</li> 4412 <li>Devices that support Ethernet networks MUST support dual-stack operation 4413 on Ethernet.</li> 4414 <li>Devices that support cellular data SHOULD support IPv6 operation 4415 (IPv6-only and possibly dual-stack) on cellular data.</li> 4416 <li>When a device is simultaneously connected to more than one network (e.g., 4417 Wi-Fi and cellular data), it MUST simultaneously meet these requirements on 4418 each network to which it is connected.</li> 4419</ul> 4420 4421<p>IPv6 MUST be enabled by default.</p> 4422 4423<p>In order to ensure that IPv6 communication is as reliable as IPv4, unicast 4424IPv6 packets sent to the device MUST NOT be dropped, even when the screen is 4425not in an active state. Redundant multicast IPv6 packets, such as repeated 4426identical Router Advertisements, MAY be rate-limited in hardware or firmware 4427if doing so is necessary to save power. In such cases, rate-limiting MUST NOT 4428cause the device to lose IPv6 connectivity on any IPv6-compliant network that 4429uses RA lifetimes of at least 180 seconds.</p> 4430 4431<p>IPv6 connectivity MUST be maintained in doze mode.</p> 4432 4433<h3 id="7_4_6_sync_settings">7.4.6. Sync Settings</h3> 4434 4435 4436<p>Device implementations MUST have the master auto-sync setting on by default so 4437that the method 4438<a href="http://developer.android.com/reference/android/content/ContentResolver.html">getMasterSyncAutomatically()</a> 4439returns “true”.</p> 4440 4441<h2 id="7_5_cameras">7.5. Cameras</h2> 4442 4443 4444<p>Device implementations SHOULD include a rear-facing camera and MAY include a 4445front-facing camera. A rear-facing camera is a camera located on the side of 4446the device opposite the display; that is, it images scenes on the far side of 4447the device, like a traditional camera. A front-facing camera is a camera 4448located on the same side of the device as the display; that is, a camera 4449typically used to image the user, such as for video conferencing and similar 4450applications.</p> 4451 4452<p>If a device implementation includes at least one camera, it SHOULD be 4453possible for an application to simultaneously allocate 3 bitmaps equal to the 4454size of the images produced by the largest-resolution camera sensor on the 4455device.</p> 4456 4457<h3 id="7_5_1_rear-facing_camera">7.5.1. Rear-Facing Camera</h3> 4458 4459 4460<p>Device implementations SHOULD include a rear-facing camera. If a device 4461implementation includes at least one rear-facing camera, it:</p> 4462 4463<ul> 4464 <li>MUST report the feature flag android.hardware.camera and 4465 android.hardware.camera.any.</li> 4466 <li>MUST have a resolution of at least 2 megapixels.</li> 4467 <li>SHOULD have either hardware auto-focus or software auto-focus implemented 4468 in the camera driver (transparent to application software).</li> 4469 <li>MAY have fixed-focus or EDOF (extended depth of field) hardware.</li> 4470 <li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST 4471 NOT be lit while an android.hardware.Camera.PreviewCallback instance has been 4472 registered on a Camera preview surface, unless the application has explicitly 4473 enabled the flash by enabling the FLASH_MODE_AUTO or FLASH_MODE_ON attributes 4474 of a Camera.Parameters object. Note that this constraint does not apply to the 4475 device’s built-in system camera application, but only to third-party 4476 applications using Camera.PreviewCallback.</li> 4477</ul> 4478 4479<h3 id="7_5_2_front-facing_camera">7.5.2. Front-Facing Camera</h3> 4480 4481 4482<p>Device implementations MAY include a front-facing camera. If a device 4483implementation includes at least one front-facing camera, it:</p> 4484 4485<ul> 4486 <li>MUST report the feature flag android.hardware.camera.any and 4487 android.hardware.camera.front.</li> 4488 <li>MUST have a resolution of at least VGA (640x480 pixels).</li> 4489 <li>MUST NOT use a front-facing camera as the default for the Camera API. The 4490 camera API in Android has specific support for front-facing cameras and device 4491 implementations MUST NOT configure the API to to treat a front-facing camera 4492 as the default rear-facing camera, even if it is the only camera on the 4493 device.</li> 4494 <li>MAY include features (such as auto-focus, flash, etc.) available to 4495 rear-facing cameras as described in 4496 <a href="#7_5_1_rear-facing_camera">section 7.5.1</a>.</li> 4497 <li>MUST horizontally reflect (i.e. mirror) the stream displayed by an app in 4498 a CameraPreview, as follows: 4499 <ul> 4500 <li>If the device implementation is capable of being rotated by user (such 4501 as automatically via an accelerometer or manually via user input), the 4502 camera preview MUST be mirrored horizontally relative to the device’s 4503 current orientation.</li> 4504 <li>If the current application has explicitly requested that the Camera 4505 display be rotated via a call to the 4506 <a href="http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)">android.hardware.Camera.setDisplayOrientation()</a> 4507 method, the camera preview MUST be mirrored horizontally relative to the 4508 orientation specified by the application.</li> 4509 <li>Otherwise, the preview MUST be mirrored along the device’s default 4510 horizontal axis.</li> 4511 </ul></li> 4512 <li>MUST mirror the image displayed by the postview in the same manner as the 4513 camera preview image stream. If the device implementation does not support 4514 postview, this requirement obviously does not apply.</li> 4515 <li>MUST NOT mirror the final captured still image or video streams returned 4516 to application callbacks or committed to media storage.</li> 4517</ul> 4518 4519<h3 id="7_5_3_external_camera">7.5.3. External Camera</h3> 4520 4521 4522<p>Device implementations with USB host mode MAY include support for an external 4523camera that connects to the USB port. If a device includes support for an 4524external camera, it:</p> 4525 4526<ul> 4527 <li>MUST declare the platform feature android.hardware.camera.external and 4528android.hardware camera.any.</li> 4529 <li>MUST support USB Video Class (UVC 1.0 or higher).</li> 4530 <li>MAY support multiple cameras.</li> 4531</ul> 4532 4533<p>Video compression (such as MJPEG) support is RECOMMENDED to enable transfer of 4534high-quality unencoded streams (i.e. raw or independently compressed picture 4535streams). Camera-based video encoding MAY be supported. If so, a simultaneous 4536unencoded/ MJPEG stream (QVGA or greater resolution) MUST be accessible to the 4537device implementation.</p> 4538 4539<h3 id="7_5_4_camera_api_behavior">7.5.4. Camera API Behavior</h3> 4540 4541 4542<p>Android includes two API packages to access the camera, the newer 4543android.hardware.camera2 API expose lower-level camera control to the app, 4544including efficient zero-copy burst/streaming flows and per-frame controls of 4545exposure, gain, white balance gains, color conversion, denoising, sharpening, 4546and more.</p> 4547 4548<p>The older API package, android.hardware.Camera, is marked as deprecated in 4549Android 5.0 but as it should still be available for apps to use Android device 4550implementations MUST ensure the continued support of the API as described in 4551this section and in the Android SDK.</p> 4552 4553<p>Device implementations MUST implement the following behaviors for the 4554camera-related APIs, for all available cameras:</p> 4555 4556<ul> 4557 <li>If an application has never called 4558 android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST 4559 use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to 4560 application callbacks.</li> 4561 <li>If an application registers an android.hardware.Camera.PreviewCallback 4562 instance and the system calls the onPreviewFrame() method when the preview 4563 format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame() 4564 must further be in the NV21 encoding format. That is, NV21 MUST be the 4565 default.</li> 4566 <li>For android.hardware.Camera, device implementations MUST support the YV12 4567 format (as denoted by the android.graphics.ImageFormat.YV12 constant) for 4568 camera previews for both front- and rear-facing cameras. (The hardware video 4569 encoder and camera may use any native pixel format, but the device 4570 implementation MUST support conversion to YV12.)</li> 4571 <li>For android.hardware.camera2, device implementations must support the 4572 android.hardware.ImageFormat.YUV_420_888 and android.hardware.ImageFormat.JPEG 4573 formats as outputs through the android.media.ImageReader API.</li> 4574</ul> 4575 4576<p>Device implementations MUST still implement the full 4577<a href="http://developer.android.com/reference/android/hardware/Camera.html">Camera 4578API</a> included in the Android SDK documentation, regardless of whether the 4579device includes hardware autofocus or other capabilities. For instance, cameras 4580that lack autofocus MUST still call any registered 4581android.hardware.Camera.AutoFocusCallback instances (even though this has no 4582relevance to a non-autofocus camera.) Note that this does apply to front-facing 4583cameras; for instance, even though most front-facing cameras do not support 4584autofocus, the API callbacks must still be “faked” as described.</p> 4585 4586<p>Device implementations MUST recognize and honor each parameter name defined 4587as a constant on the 4588<a href="http://developer.android.com/reference/android/hardware/Camera.Parameters.html">android.hardware.Camera.Parameters</a> 4589class, if the underlying hardware supports the feature. If the device hardware 4590does not support a feature, the API must behave as documented. Conversely, 4591device implementations MUST NOT honor or recognize string constants passed to 4592the android.hardware.Camera.setParameters() method other than those documented 4593as constants on the android.hardware.Camera.Parameters. That is, device 4594implementations MUST support all standard Camera parameters if the hardware 4595allows, and MUST NOT support custom Camera parameter types. For instance, device 4596implementations that support image capture using high dynamic range (HDR) 4597imaging techniques MUST support camera parameter Camera.SCENE_MODE_HDR.</p> 4598 4599<p>Because not all device implementations can fully support all the features of 4600the android.hardware.camera2 API, device implementations MUST report the proper 4601level of support with the 4602<a href="https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#INFO_SUPPORTED_HARDWARE_LEVEL">android.info.supportedHardwareLevel</a> 4603property as described in the Android SDK and report the appropriate 4604<a href="http://source.android.com/devices/camera/versioning.html">framework 4605feature flags</a>.</p> 4606 4607<p>Device implementations MUST also declare its Individual camera capabilities 4608of android.hardware.camera2 via the android.request.availableCapabilities 4609property and declare the appropriate 4610<a href="http://source.android.com/devices/camera/versioning.html">feature 4611flags</a>; a device must define the feature flag if any of its attached camera 4612devices supports the feature.</p> 4613 4614<p>Device implementations MUST broadcast the Camera.ACTION_NEW_PICTURE intent 4615whenever a new picture is taken by the camera and the entry of the picture has 4616been added to the media store.</p> 4617 4618<p>Device implementations MUST broadcast the Camera.ACTION_NEW_VIDEO intent 4619whenever a new video is recorded by the camera and the entry of the picture has 4620been added to the media store.</p> 4621 4622<h3 id="7_5_5_camera_orientation">7.5.5. Camera Orientation</h3> 4623 4624 4625<p>Both front- and rear-facing cameras, if present, MUST be oriented so that the 4626long dimension of the camera aligns with the screen’s long dimension. That 4627is, when the device is held in the landscape orientation, cameras MUST capture 4628images in the landscape orientation. This applies regardless of the 4629device’s natural orientation; that is, it applies to landscape-primary 4630devices as well as portrait-primary devices.</p> 4631 4632<h2 id="7_6_memory_and_storage">7.6. Memory and Storage</h2> 4633 4634 4635<h3 id="7_6_1_minimum_memory_and_storage">7.6.1. Minimum Memory and Storage</h3> 4636 4637<div class="note"> 4638<p>Android Television devices MUST have at least 5GB of non-volatile storage 4639available for application private data.</p> 4640</div> 4641 4642 4643<p>The memory available to the kernel and userspace on device implementations 4644MUST be at least equal or larger than the minimum values specified by the 4645following table. (See <a href="#7_1_1_screen_configuration">section 7.1.1</a> 4646for screen size and density definitions.)</p> 4647<table> 4648 <tr> 4649 <th>Density and screen size</th> 4650 <th>32-bit device</th> 4651 <th>64-bit device</th> 4652 </tr> 4653 <tr> 4654 <td>Android Watch devices (due to smaller screens)</td> 4655 <td>416MB</td> 4656 <td>Not applicable</td> 4657 </tr> 4658 <tr> 4659 <td><ul> 4660 <li class="table_list">280dpi or lower on small/normal screens</li> 4661 <li class="table_list">mdpi or lower on large screens</li> 4662 <li class="table_list">ldpi or lower on extra large screens</li> 4663 </ul></td> 4664 <td>424MB</td> 4665 <td>704MB</td> 4666 </tr> 4667 <tr> 4668 <td><ul> 4669 <li class="table_list">xhdpi or higher on small/normal screens</li> 4670 <li class="table_list">hdpi or higher on large screens</li> 4671 <li class="table_list">mdpi or higher on extra large screens</li></ul></td> 4672 <td>512MB</td> 4673 <td>832MB</td> 4674 </tr> 4675 <tr> 4676 <td><ul> 4677 <li class="table_list">400dpi or higher on small/normal screens</li> 4678 <li class="table_list">xhdpi or higher on large screens</li> 4679 <li class="table_list">tvdpi or higher on extra large screens</li></ul></td> 4680 <td>896MB</td> 4681 <td>1280MB</td> 4682 </tr> 4683 <tr> 4684 <td><ul> 4685 <li class="table_list">560dpi or higher on small/normal screens</li> 4686 <li class="table_list">400dpi or higher on large screens</li> 4687 <li class="table_list">xhdpi or higher on extra large screens</li></ul></td> 4688 <td>1344MB</td> 4689 <td>1824MB</td> 4690 </tr> 4691</table> 4692 4693 4694<p>The minimum memory values MUST be in addition to any memory space already 4695dedicated to hardware components such as radio, video, and so on that is not 4696under the kernel’s control.</p> 4697 4698<p>Device implementations with less than 512MB of memory available to the kernel 4699and userspace, unless an Android Watch, MUST return the value "true" for 4700ActivityManager.isLowRamDevice().</p> 4701 4702<p>Android Television devices MUST have at least 5GB and other device 4703implementations MUST have at least 1.5GB of non-volatile storage available for 4704application private data. That is, the /data partition MUST be at least 5GB for 4705Android Television devices and at least 1.5GB for other device implementations. 4706Device implementations that run Android are <strong>STRONGLY 4707RECOMMENDED</strong> to have at least 3GB of non-volatile storage for 4708application private data so they will be able to upgrade to the future platform 4709releases.</p> 4710 4711<p>The Android APIs include a 4712<a href="http://developer.android.com/reference/android/app/DownloadManager.html">Download 4713Manager</a> that applications MAY use to download data files. The device 4714implementation of the Download Manager MUST be capable of downloading individual 4715files of at least 100MB in size to the default “cache” location.</p> 4716 4717<h3 id="7_6_2_application_shared_storage">7.6.2. Application Shared Storage</h3> 4718 4719 4720<p>Device implementations MUST offer shared storage for applications also often 4721referred as “shared external storage”.</p> 4722 4723<p>Device implementations MUST be configured with shared storage mounted by 4724default, “out of the box”. If the shared storage is not mounted on 4725the Linuxpath /sdcard, then the device MUST include a Linux symbolic link from 4726/sdcard to the actual mount point.</p> 4727 4728<p>Device implementations MAY have hardware for user-accessible removable 4729storage, such as a Secure Digital (SD) card slot. If this slot is used to 4730satisfy the shared storage requirement, the device implementation:</p> 4731 4732<ul> 4733 <li>MUST implement a toast or pop-up user interface warning the user when 4734 there is no SD card.</li> 4735 <li>MUST include a FAT-formatted SD card 1GB in size or larger OR show on the 4736 box and other material available at time of purchase that the SD card has to 4737 be separately purchased.</li> 4738 <li>MUST mount the SD card by default.</li> 4739</ul> 4740 4741<p>Alternatively, device implementations MAY allocate internal (non-removable) 4742storage as shared storage for apps as included in the upstream Android Open 4743Source Project; device implementations SHOULD use this configuration and 4744software implementation. If a device implementation uses internal 4745(non-removable) storage to satisfy the shared storage requirement, that storage 4746MUST be 1GB in size or larger and mounted on /sdcard (or /sdcard MUST be a 4747symbolic link to the physical location if it is mounted elsewhere).</p> 4748 4749<p>Device implementations MUST enforce as documented the 4750android.permission.WRITE_EXTERNAL_STORAGE permission on this shared storage. 4751Shared storage MUST otherwise be writable by any application that obtains that 4752permission.</p> 4753 4754<p>Device implementations that include multiple shared storage paths (such as 4755both an SD card slot and shared internal storage) MUST NOT allow Android 4756applications to write to the secondary external storage, except for their 4757package-specific directories on the secondary external storage, but SHOULD 4758expose content from both storage paths transparently through Android’s 4759media scanner service and android.provider.MediaStore.</p> 4760 4761<p>Regardless of the form of shared storage used, if the device implementation 4762has a USB port with USB peripheral mode support, it MUST provide some mechanism 4763to access the contents of shared storage from a host computer. Device 4764implementations MAY use USB mass storage, but SHOULD use Media Transfer Protocol 4765to satisfy this requirement. If the device implementation supports Media 4766Transfer Protocol, it:</p> 4767 4768<ul> 4769 <li>SHOULD be compatible with the reference Android MTP host, 4770 <a href="http://www.android.com/filetransfer">Android File Transfer</a>.</li> 4771 <li>SHOULD report a USB device class of 0x00.</li> 4772 <li>SHOULD report a USB interface name of 'MTP'.</li> 4773</ul> 4774 4775<h3 id="7_6_3_adoptable_storage">7.6.3. Adoptable Storage</h3> 4776 4777<p>Device implementations are STRONGLY RECOMMENDED to implement 4778<a href="http://source.android.com/devices/storage/adoptable.html">adoptable 4779storage</a> if the removable storage device port is in a long-term stable 4780location, such as within the battery compartment or other protective cover.</p> 4781 4782<p>Device implementations such as a television, MAY enable adoption through USB 4783ports as the device is expected to be static and not mobile. But for other 4784device implementations that are mobile in nature, it is STRONGLY RECOMMENDED to 4785implement the adoptable storage in a long-term stable location, since 4786accidentally disconnecting them can cause data loss/corruption.</p> 4787 4788<h2 id="7_7_usb">7.7. USB</h2> 4789 4790 4791<p>Device implementations SHOULD support USB peripheral mode and SHOULD support 4792USB host mode.</p> 4793 4794<p>If a device implementation includes a USB port supporting peripheral mode: 4795</p> 4796 4797<ul> 4798 <li>The port MUST be connectable to a USB host that has a standard type-A or 4799 type-C USB port.</li> 4800 <li>The port SHOULD use micro-A, micro-AB or type-C USB form factor. Existing 4801 and new Android devices are <strong>STRONGLY RECOMMENDED to meet these 4802 requirements</strong> so they will be able to upgrade to the future platform 4803 releases.</li> 4804 <li>The port SHOULD be centered in the middle of an edge. Device 4805 implementations SHOULD either locate the port on the bottom of the device 4806 (according to natural orientation) or enable software screen rotation for all 4807 apps (including home screen), so that the display draws correctly when the 4808 device is oriented with the port at bottom. Existing and new Android devices 4809 are <strong>STRONGLY RECOMMENDED to meet these requirements</strong> so they 4810 will be able to upgrade to future platform releases.</li> 4811 <li>It MUST allow a USB host connected with the Android device to access the 4812 contents of the shared storage volume using either USB mass storage or Media 4813 Transfer Protocol.</li> 4814 <li>It SHOULD implement the Android Open Accessory (AOA) API and specification 4815 as documented in the Android SDK documentation, and if it is an Android 4816 Handheld device it MUST implement the AOA API. Device implementations 4817 implementing the AOA specification: 4818 <ul> 4819 <li>MUST declare support for the hardware feature 4820 <a href="http://developer.android.com/guide/topics/connectivity/usb/accessory.html">android.hardware.usb.accessory</a>. 4821 </li> 4822 <li>MUST implement the 4823 <a href="http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO">USB 4824 audio class</a>as documented in the Android SDK documentation.</li> 4825 <li>The USB mass storage class MUST include the string "android" at the end 4826 of the interface description <code>iInterface</code> string of the USB mass 4827 storage</li> 4828 </ul> 4829 </li> 4830 <li>It SHOULD implement support to draw 1.5 A current during HS chirp and 4831 traffic as specified in the 4832 <a href="http://www.usb.org/developers/docs/devclass_docs/USB_Battery_Charging_1.2.pdf">USB 4833 battery charging specification</a>. Existing and new Android devices are 4834 <strong>STRONGLY RECOMMENDED to meet these requirements</strong> so they will 4835 be able to upgrade to the future platform releases.</li> 4836 <li>The value of iSerialNumber in USB standard device descriptor MUST be equal 4837 to the value of android.os.Build.SERIAL.</li> 4838</ul> 4839 4840<p>If a device implementation includes a USB port supporting host mode, it:</p> 4841 4842<ul> 4843 <li>SHOULD use a type-C USB port, if the device implementation supports USB 4844 3.1.</li> 4845 <li>MAY use a non-standard port form factor, but if so MUST ship with a cable 4846 or cables adapting the port to a standard type-A or type-C USB port.</li> 4847 <li>MAY use a micro-AB USB port, but if so SHOULD ship with a cable or cables 4848 adapting the port to a standard type-A or type-C USB port.</li> 4849 <li>is <strong>STRONGLY RECOMMENDED</strong> to implement the 4850 <a href="http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO">USB 4851 audio class</a> as documented in the Android SDK documentation.</li> 4852 <li>MUST implement the Android USB host API as documented in the Android SDK, 4853 and MUST declare support for the hardware feature 4854 <a href="http://developer.android.com/guide/topics/connectivity/usb/host.html">android.hardware.usb.host</a>. 4855 </li> 4856 <li>SHOULD support the Charging Downstream Port output current range of 1.5 A 4857 ~ 5 A as specified in the 4858 <a href="http://www.usb.org/developers/docs/devclass_docs/USB_Battery_Charging_1.2.pdf">USB 4859 Battery Charging Specifications</a>.</li> 4860</ul> 4861 4862<h2 id="7_8_audio">7.8. Audio</h2> 4863 4864 4865<h3 id="7_8_1_microphone">7.8.1. Microphone</h3> 4866 4867<div class="note"> 4868<p>Android Handheld, Watch, and Automotive implementations MUST include a 4869microphone.</p> 4870</div> 4871 4872 4873<p>Device implementations MAY omit a microphone. However, if a device 4874implementation omits a microphone, it MUST NOT report the 4875android.hardware.microphone feature constant, and MUST implement the audio 4876recording API at least as no-ops, per 4877<a href="#7_hardware_compatibility">section 7</a>. Conversely, device 4878implementations that do possess a microphone:</p> 4879 4880<ul> 4881 <li>MUST report the android.hardware.microphone feature constant.</li> 4882 <li>MUST meet the audio recording requirements in 4883 <a href="#5_4_audio_recording">section 5.4</a>.</li> 4884 <li>MUST meet the audio latency requirements in 4885 <a href="#5_6_audio_latency">section 5.6</a>.</li> 4886 <li>STRONGLY RECOMMENDED to support near-ultrasound recording as described in 4887 <a href="#7_8_3_near_ultrasound">section 7.8.3</a>.</li> 4888</ul> 4889 4890<h3 id="7_8_2_audio_output">7.8.2. Audio Output</h3> 4891 4892<div class="note"> 4893<p>Android Watch devices MAY include an audio output.</p> 4894</div> 4895 4896<p>Device implementations including a speaker or with an audio/multimedia output 4897port for an audio output peripheral as a headset or an external speaker:</p> 4898 4899<ul> 4900 <li>MUST report the android.hardware.audio.output feature constant.</li> 4901 <li>MUST meet the audio playback requirements in 4902 <a href="#5_5_audio_playback">section 5.5</a>.</li> 4903 <li>MUST meet the audio latency requirements in 4904 <a href="#5_6_audio_latency">section 5.6</a>.</li> 4905 <li>STRONGLY RECOMMENDED to support near-ultrasound playback as described in 4906 <a href="#7_8_3_near_ultrasound">section 7.8.3</a>.</li> 4907</ul> 4908 4909<p>Conversely, if a device implementation does not include a speaker or audio 4910output port, it MUST NOT report the android.hardware.audio output feature, and 4911MUST implement the Audio Output related APIs as no-ops at least. </p> 4912 4913<p>Android Watch device implementation MAY but SHOULD NOT have audio output, but 4914other types of Android device implementations MUST have an audio output and 4915declare android.hardware.audio.output.</p> 4916 4917<h4 id="7_8_2_1_analog_audio_ports">7.8.2.1. Analog Audio Ports</h4> 4918 4919 4920<p>In order to be compatible with the 4921<a href="http://source.android.com/accessories/headset-spec.html">headsets and 4922other audio accessories</a> using the 3.5mm audio plug across the Android 4923ecosystem, if a device implementation includes one or more analog audio ports, 4924at least one of the audio port(s) SHOULD be a 4 conductor 3.5mm audio jack. If a 4925device implementation has a 4 conductor 3.5mm audio jack, it:</p> 4926 4927<ul> 4928 <li>MUST support audio playback to stereo headphones and stereo headsets with 4929 a microphone, and SHOULD support audio recording from stereo headsets with a 4930 microphone.</li> 4931 <li>MUST support TRRS audio plugs with the CTIA pin-out order, and SHOULD 4932 support audio plugs with the OMTP pin-out order.</li> 4933 <li>MUST support the detection of microphone on the plugged in audio 4934 accessory, if the device implementation supports a microphone, and broadcast 4935 the android.intent.action.HEADSET_PLUG with the extra value microphone set as 4936 1.</li> 4937 <li>SHOULD support the detection and mapping to the keycodes for the following 4938 3 ranges of equivalent impedance between the microphone and ground conductors 4939 on the audio plug: 4940 <ul> 4941 <li><strong>70 ohm or less</strong>: KEYCODE_HEADSETHOOK</li> 4942 <li><strong>210-290 Ohm</strong>: KEYCODE_VOLUME_UP</li> 4943 <li><strong>360-680 Ohm</strong>: KEYCODE_VOLUME_DOWN</li> 4944 </ul></li> 4945 <li>SHOULD support the detection and mapping to the keycode for the following 4946 range of equivalent impedance between the microphone and ground conductors on 4947 the audio plug: 4948 <ul> 4949 <li><strong>110-180 Ohm: </strong>KEYCODE_VOICE_ASSIST</li> 4950 </ul></li> 4951 <li>MUST trigger ACTION_HEADSET_PLUG upon a plug insert, but only after all 4952 contacts on plug are touching their relevant segments on the jack.</li> 4953 <li>MUST be capable of driving at least 150mV ± 10% of output voltage 4954 on a 32 Ohm speaker impedance.</li> 4955 <li>MUST have a microphone bias voltage between 1.8V ~ 2.9V.</li> 4956</ul> 4957 4958<h3 id="7_8_3_near_ultrasound">7.8.3. Near-Ultrasound </h3> 4959 4960<p>Near-Ultrasound audio is the 18.5 kHz to 20 kHz band. Device implementations 4961MUST correctly report the support of near-ultrasound audio capability via the 4962<a href="http://developer.android.com/reference/android/media/AudioManager.html#getProperty(java.lang.String)">AudioManager.getProperty</a> 4963API as follows: 4964</p> 4965 4966<ul> 4967 <li>If 4968 <a href="http://developer.android.com/reference/android/media/AudioManager.html#PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND">PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND</a> 4969 is "true", then 4970 <ul> 4971 <li>The microphone's mean power response in the 18.5 kHz to 20 kHz band MUST 4972 be no more than 15 dB below the response at 2 kHz.</li> 4973 <li>The signal to noise ratio of the microphone MUST be no lower than 80 dB. 4974 </li> 4975 </ul> 4976 </li> 4977 <li>If 4978 <a href="http://developer.android.com/reference/android/media/AudioManager.html#PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND">PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND</a> 4979 is "true", then the speaker's mean response in 18.5 kHz - 20 kHz MUST be no 4980 lower than 40 dB below the response at 2 kHz.</li> 4981</ul> 4982 4983<h1 id="8_performance_power">8. Performance and Power</h1> 4984 4985 4986<p>Some minimum performance and power criteria are critical to the user 4987experience and impact the baseline assumptions developers would have when 4988developing an app. Android Watch devices SHOULD and other type of device 4989implementations MUST meet the following criteria.</p> 4990 4991<h2 id="8_1_user_experience_consistency">8.1. User Experience Consistency</h2> 4992 4993 4994<p>Device implementations MUST provide a smooth user interface by ensuring a 4995consistent frame rate and response times for applications and games. Device 4996implementations MUST meet the following requirements:</p> 4997 4998<ul> 4999 <li><strong>Consistent frame latency</strong>. Inconsistent frame latency or a 5000 delay to render frames MUST NOT happen more often than 5 frames in a second, 5001 and SHOULD be below 1 frames in a second.</li> 5002 <li><strong>User interface latency</strong>. Device implementations MUST 5003 ensure low latency user experience by scrolling a list of 10K list entries as 5004 defined by the Android Compatibility Test Suite (CTS) in less than 36 secs. 5005 </li> 5006 <li><strong>Task switching</strong>. When multiple applications have been 5007 launched, re-launching an already-running application after it has been 5008 launched MUST take less than 1 second.</li> 5009</ul> 5010 5011<h2 id="8_2_file_i_o_access_performance">8.2. File I/O Access Performance</h2> 5012 5013 5014<p>Device implementations MUST ensure internal storage file access performance 5015consistency for read and write operations.</p> 5016 5017<ul> 5018 <li><strong>Sequential write</strong>. Device implementations MUST ensure a 5019 sequential write performance of at least 5MB/s for a 256MB file using 10MB 5020 write buffer.</li> 5021 <li><strong>Random write</strong>. Device implementations MUST ensure a random 5022 write performance of at least 0.5MB/s for a 256MB file using 4KB write buffer. 5023 </li> 5024 <li><strong>Sequential read</strong>. Device implementations MUST ensure a 5025 sequential read performance of at least 15MB/s for a 256MB file using 10MB 5026 write buffer.</li> 5027 <li><strong>Random read</strong>. Device implementations MUST ensure a random 5028 read performance of at least 3.5MB/s for a 256MB file using 4KB write buffer. 5029 </li> 5030</ul> 5031 5032<h2 id="8_3_power_saving_modes">8.3. Power-Saving Modes</h2> 5033 5034<p>All apps exempted from App Standby and/or Doze mode MUST be made visible to 5035the end user. Further, the triggering, maintenance, wakeup algorithms and 5036the use of Global system settings of these power-saving modes MUST not deviate 5037from the Android Open Source Project.</p> 5038 5039<h2 id="8_4_power_consumption_accounting">8.4. Power Consumption Accounting</h2> 5040 5041<p>A more accurate accounting and reporting of the power consumption provides 5042the app developer both the incentives and the tools to optimize the power usage 5043pattern of the application. Therefore, device implementations:</p> 5044 5045<ul> 5046 <li>MUST be able to track hardware component power usage and attribute that 5047 power usage to specific applications. Specifically, implementations: 5048 <ul> 5049 <li>MUST provide a per-component power profile that defines the 5050 <a href="http://source.android.com/devices/tech/power/values.html">current 5051 consumption value</a> for each hardware component and the approximate 5052 battery drain caused by the components over time as documented in the 5053 Android Open Source Project site.</li> 5054 <li>MUST report all power consumption values in milliampere hours (mAh). 5055 </li> 5056 <li>SHOULD be attributed to the hardware component itself if unable to 5057 attribute hardware component power usage to an application.</li> 5058 <li>MUST report CPU power consumption per each process's UID. The Android 5059 Open Source Project meets the requirement through the 5060 <code>uid_cputime</code> kernel module implementation.</li> 5061 </ul> 5062 </li> 5063 <li>MUST make this power usage available via the 5064 <a href="http://source.android.com/devices/tech/power/batterystats.html"><code>adb 5065 shell dumpsys batterystats</code></a> shell command to the app developer.</li> 5066 <li>MUST honor the 5067 <a href="http://developer.android.com/reference/android/content/Intent.html#ACTION_POWER_USAGE_SUMMARY">android.intent.action.POWER_USAGE_SUMMARY</a> 5068 intent and display a settings menu that shows this power usage.</li> 5069</ul> 5070 5071<h1 id="9_security_model_compatibility">9. Security Model Compatibility</h1> 5072 5073 5074<p>Device implementations MUST implement a security model consistent with the 5075Android platform security model as defined in 5076<a href="http://developer.android.com/guide/topics/security/permissions.html">Security 5077and Permissions reference document</a> in the APIs in the Android developer 5078documentation. Device implementations MUST support installation of self-signed 5079applications without requiring any additional permissions/certificates from any 5080third parties/authorities. Specifically, compatible devices MUST support the 5081security mechanisms described in the follow subsections.</p> 5082 5083<h2 id="9_1_permissions">9.1. Permissions</h2> 5084 5085 5086<p>Device implementations MUST support the 5087<a href="http://developer.android.com/guide/topics/security/permissions.html">Android 5088permissions model</a> as defined in the Android developer documentation. 5089Specifically, implementations MUST enforce each permission defined as described 5090in the SDK documentation; no permissions may be omitted, altered, or ignored. 5091Implementations MAY add additional permissions, provided the new permission ID 5092strings are not in the android.* namespace.</p> 5093 5094<p>Permissions with a protection level of dangerous are runtime permissions. 5095Applications with targetSdkVersion > 22 request them at runtime. Device 5096implementations:</p> 5097 5098<ul> 5099 <li>MUST show a dedicated interface for the user to decide whether to grant 5100 the requested runtime permissions and also provide an interface for the user 5101 to manage runtime permissions.</li> 5102 <li>MUST have one and only one implementation of both user interfaces.</li> 5103 <li>MUST NOT grant any runtime permissions to preinstalled apps unless: 5104 <ul> 5105 <li>the user's consent can be obtained before the application uses it</li> 5106 <li>the runtime permissions are associated with an intent pattern for which 5107 the preinstalled application is set as the default handler</li> 5108 </ul> 5109 </li> 5110</ul> 5111 5112<h2 id="9_2_uid_and_process_isolation">9.2. UID and Process Isolation</h2> 5113 5114 5115<p>Device implementations MUST support the Android application sandbox model, in 5116which each application runs as a unique Unixstyle UID and in a separate 5117process. Device implementations MUST support running multiple applications as 5118the same Linux user ID, provided that the applications are properly signed and 5119constructed, as defined in the 5120<a href="http://developer.android.com/guide/topics/security/permissions.html">Security 5121and Permissions reference</a>.</p> 5122 5123<h2 id="9_3_filesystem_permissions">9.3. Filesystem Permissions</h2> 5124 5125 5126<p>Device implementations MUST support the Android file access permissions model 5127as defined in the 5128<a href="http://developer.android.com/guide/topics/security/permissions.html">Security 5129and Permissions reference</a>.</p> 5130 5131<h2 id="9_4_alternate_execution_environments">9.4. Alternate Execution 5132Environments</h2> 5133 5134 5135<p>Device implementations MAY include runtime environments that execute 5136applications using some other software or technology than the Dalvik Executable 5137Format or native code. However, such alternate execution environments MUST NOT 5138compromise the Android security model or the security of installed Android 5139applications, as described in this section.</p> 5140 5141<p>Alternate runtimes MUST themselves be Android applications, and abide by the 5142standard Android security model, as described elsewhere in 5143<a href="#9_security_model_compatibility">section 9</a>.</p> 5144 5145<p>Alternate runtimes MUST NOT be granted access to resources protected by 5146permissions not requested in the runtime’s AndroidManifest.xml file via 5147the <uses-permission> mechanism.</p> 5148 5149<p>Alternate runtimes MUST NOT permit applications to make use of features 5150protected by Android permissions restricted to system applications.</p> 5151 5152<p>Alternate runtimes MUST abide by the Android sandbox model. Specifically, 5153alternate runtimes:</p> 5154 5155<ul> 5156 <li>SHOULD install apps via the PackageManager into separate Android sandboxes 5157 (Linux user IDs, etc.).</li> 5158 <li>MAY provide a single Android sandbox shared by all applications using the 5159 alternate runtime.</li> 5160 <li>Installed applications using an alternate runtime MUST NOT reuse the 5161 sandbox of any other app installed on the device, except through the standard 5162 Android mechanisms of shared user ID and signing certificate.</li> 5163 <li>MUST NOT launch with, grant, or be granted access to the sandboxes 5164 corresponding to other Android applications.</li> 5165 <li>MUST NOT be launched with, be granted, or grant to other applications any 5166 privileges of the superuser (root), or of any other user ID.</li> 5167</ul> 5168 5169<p>The .apk files of alternate runtimes MAY be included in the system image of a 5170device implementation, but MUST be signed with a key distinct from the key used 5171to sign other applications included with the device implementation.</p> 5172 5173<p>When installing applications, alternate runtimes MUST obtain user consent for 5174the Android permissions used by the application. If an application needs to make 5175use of a device resource for which there is a corresponding Android permission 5176(such as Camera, GPS, etc.), the alternate runtime MUST inform the user that the 5177application will be able to access that resource. If the runtime environment 5178does not record application capabilities in this manner, the runtime environment 5179MUST list all permissions held by the runtime itself when installing any 5180application using that runtime.</p> 5181 5182<h2 id="9_5_multi-user_support">9.5. Multi-User Support</h2> 5183 5184<div class="note"> 5185<p>This feature is optional for all device types.</p> 5186</div> 5187 5188 5189<p>Android includes 5190<a href="http://developer.android.com/reference/android/os/UserManager.html">support 5191for multiple users</a> and provides support for full user isolation. Device 5192implementations MAY enable multiple users, but when enabled MUST meet the 5193following requirements related to 5194<a href="http://source.android.com/devices/storage/traditional.html">multi-user 5195support</a>:</p> 5196 5197<ul> 5198 <li>Device implementations that do not declare the android.hardware.telephony 5199 feature flag MUST support restricted profiles, a feature that allows device 5200 owners to manage additional users and their capabilities on the device. With 5201 restricted profiles, device owners can quickly set up separate environments 5202 for additional users to work in, with the ability to manage finer-grained 5203 restrictions in the apps that are available in those environments.</li> 5204 <li>Conversely device implementations that declare the 5205 android.hardware.telephony feature flag MUST NOT support restricted profiles 5206 but MUST align with the AOSP implementation of controls to enable /disable 5207 other users from accessing the voice calls and SMS.</li> 5208 <li>Device implementations MUST, for each user, implement a security model 5209 consistent with the Android platform security model as defined in 5210 <a href="http://developer.android.com/guide/topics/security/permissions.html">Security 5211 and Permissions reference document</a> in the APIs.</li> 5212 <li>Each user instance on an Android device MUST have separate and isolated 5213 external storage directories. Device implementations MAY store multiple users' 5214 data on the same volume or filesystem. However, the device implementation MUST 5215 ensure that applications owned by and running on behalf a given user cannot 5216 list, read, or write to data owned by any other user. Note that removable 5217 media, such as SD card slots, can allow one user to access another’s 5218 data by means of a host PC. For this reason, device implementations that use 5219 removable media for the external storage APIs MUST encrypt the contents of the 5220 SD card if multiuser is enabled using a key stored only on non-removable media 5221 accessible only to the system. As this will make the media unreadable by a 5222 host PC, device implementations will be required to switch to MTP or a similar 5223 system to provide host PCs with access to the current user’s data. 5224 Accordingly, device implementations MAY but SHOULD NOT enable multi-user if 5225 they use 5226 <a href="http://developer.android.com/reference/android/os/Environment.html">removable 5227 media</a> for primary external storage.</li> 5228</ul> 5229 5230<h2 id="9_6_premium_sms_warning">9.6. Premium SMS Warning</h2> 5231 5232 5233<p>Android includes support for warning users of any outgoing 5234<a href="http://en.wikipedia.org/wiki/Short_code">premium SMS message</a>. 5235Premium SMS messages are text messages sent to a service registered with a 5236carrier that may incur a charge to the user. Device implementations that declare 5237support for android.hardware.telephony MUST warn users before sending a SMS 5238message to numbers identified by regular expressions defined in 5239/data/misc/sms/codes.xml file in the device. The upstream Android Open Source 5240Project provides an implementation that satisfies this requirement.</p> 5241 5242<h2 id="9_7_kernel_security_features">9.7. Kernel Security Features</h2> 5243 5244 5245<p>The Android Sandbox includes features that use the Security-Enhanced Linux 5246(SELinux) mandatory access control (MAC) system and other security features in 5247the Linux kernel. SELinux or any other security features implemented below 5248the Android framework:</p> 5249 5250<ul> 5251 <li>MUST maintain compatibility with existing applications.</li> 5252 <li>MUST NOT have a visible user interface when a security violation is 5253 detected and successfully blocked, but MAY have a visible user interface when 5254 an unblocked security violation occurs resulting in a successful exploit.</li> 5255 <li>SHOULD NOT be user or developer configurable.</li> 5256</ul> 5257 5258<p>If any API for configuration of policy is exposed to an application that can 5259affect another application (such as a Device Administration API), the API MUST 5260NOT allow configurations that break compatibility.</p> 5261 5262<p>Devices MUST implement SELinux or, if using a kernel other than Linux, an 5263equivalent mandatory access control system. Devices MUST also meet the 5264following requirements, which are satisfied by the reference implementation 5265in the upstream Android Open Source Project.</p> 5266 5267<p>Device implementations:</p> 5268 5269<ul> 5270 <li>MUST set SELinux to global enforcing mode.</li> 5271 <li>MUST configure all domains in enforcing mode. No permissive mode domains 5272 are allowed, including domains specific to a device/vendor.</li> 5273 <li>MUST NOT modify, omit, or replace the neverallow rules present within the 5274 system/sepolicy folder provided in the upstream Android Open Source Project 5275 (AOSP) and the policy MUST compile with all neverallow rules present, for both 5276 AOSP SELinux domains as well as device/vendor specific domains.</li> 5277</ul> 5278 5279<p>Device implementations SHOULD retain the default SELinux policy provided in 5280the system/sepolicy folder of the upstream Android Open Source Project and 5281only further add to this policy for their own device-specific configuration. 5282Device implementations MUST be compatible with the upstream Android Open Source 5283Project.</p> 5284 5285<h2 id="9_8_privacy">9.8. Privacy</h2> 5286 5287<p>If the device implements functionality in the system that captures the 5288contents displayed on the screen and/or records the audio stream played on the 5289device, it MUST continuously notify the user whenever this functionality is 5290enabled and actively capturing/recording.</p> 5291 5292<p>If a device implementation has a mechanism that routes network data traffic 5293through a proxy server or VPN gateway by default (for example, preloading a VPN 5294service with android.permission.CONTROL_VPN granted), the device implementation 5295MUST ask for the user's consent before enabling that mechanism.</p> 5296 5297<p>If a device implementation has a USB port with USB peripheral mode support, 5298it MUST present a user interface asking for the user's consent before allowing 5299access to the contents of the shared storage over the USB port.</p> 5300 5301<h2 id="9_9_full-disk_encryption">9.9. Full-Disk Encryption</h2> 5302 5303<div class="note"> 5304<p>Optional for Android device implementations without a lock screen.</p> 5305</div> 5306 5307<p>If the device implementation supports a secure lock screen reporting 5308"<code>true</code>" for 5309<a href="http://developer.android.com/reference/android/app/KeyguardManager.html#isDeviceSecure()">KeyguardManager.isDeviceSecure()</a>, 5310and is not a device with restricted memory as reported through the 5311ActivityManager.isLowRamDevice() method, then the device MUST support full-disk 5312<a href="http://source.android.com/devices/tech/security/encryption/index.html">encryption</a> 5313of the application private data (/data partition), as well as the application 5314shared storage partition (/sdcard partition) if it is a permanent, non-removable 5315part of the device.</p> 5316 5317<p>For device implementations supporting full-disk encryption and with Advanced 5318Encryption Standard (AES) crypto performance above 50MiB/sec, the full-disk 5319encryption MUST be enabled by default at the time the user has completed the 5320out-of-box setup experience. If a device implementation is already launched on 5321an earlier Android version with full-disk encryption disabled by default, such a 5322device cannot meet the requirement through a system software update and thus MAY 5323be exempted.</p> 5324 5325<p>Encryption MUST use AES with a key of 128-bits (or greater) and a mode designed 5326for storage (for example, AES-XTS, AES-CBC-ESSIV). The encryption key MUST NOT 5327be written to storage at any time without being encrypted. Other than when in 5328active use, the encryption key SHOULD be AES encrypted with the lockscreen 5329passcode stretched using a slow stretching algorithm (e.g. PBKDF2 or scrypt). 5330If the user has not specified a lockscreen passcode or has disabled use of the 5331passcode for encryption, the system SHOULD use a default passcode to wrap the 5332encryption key. If the device provides a hardware-backed keystore, the password 5333stretching algorithm MUST be cryptographically bound to that keystore. The 5334encryption key MUST NOT be sent off the device (even when wrapped with the user 5335passcode and/or hardware bound key). The upstream Android Open Source project 5336provides a preferred implementation of this feature based on the Linux kernel 5337feature dm-crypt.</p> 5338 5339<h2 id="9_10_verified_boot">9.10. Verified Boot</h2> 5340 5341<p> 5342Verified boot is a feature that guarantees the integrity of the device software. 5343If a device implementation supports the feature, it MUST: 5344</p> 5345<ul> 5346 <li>Declare the platform feature flag android.software.verified_boot.</li> 5347 <li>Perform verification on every boot sequence.</li> 5348 <li>Start verification from an immutable hardware key that is the root of 5349 trust and go all the way up to the system partition.</li> 5350 <li>Implement each stage of verification to check the integrity and 5351 authenticity of all the bytes in the next stage before executing the code in 5352 the next stage.</li> 5353 <li>Use verification algorithms as strong as current recommendations from NIST 5354 for hashing algorithms (SHA-256) and public key sizes (RSA-2048).</li> 5355</ul> 5356 5357<p>The upstream Android Open Source Project provides a preferred implementation 5358of this feature based on the Linux kernel feature dm-verity.</p> 5359 5360<p>Starting from Android 6.0, device implementations with Advanced Encryption 5361Standard (AES) crypto perfomance above 50MiB/seconds MUST support verified boot 5362for device integrity. If a device implementation is already launched without 5363supporting verified boot on an earlier version of Android, such a device can not 5364add support for this feature with a system software update and thus are exempted 5365from the requirement.</p> 5366 5367<h2 id="9_11_keys_and_credentials">9.11. Keys and Credentials</h2> 5368 5369<p>The <a href="https://developer.android.com/training/articles/keystore.html">Android 5370Keystore System</a> allows app developers to store cryptographic keys in a 5371container and use them in cryptographic 5372operations through the 5373<a href="https://developer.android.com/reference/android/security/KeyChain.html">KeyChain 5374API</a> or the 5375<a href="https://developer.android.com/reference/java/security/KeyStore.html">Keystore 5376API</a>.</p> 5377 5378<p>All Android device implementations MUST meet the following requirements:</p> 5379 5380<ul> 5381 <li>SHOULD not limit the number of keys that can be generated, and MUST at 5382 least allow more than 8,192 keys to be imported.</li> 5383 <li>The lock screen authentication MUST rate limit attempts and SHOULD have an 5384 exponential backoff algorithm as implemented in the Android Open Source 5385 Project.</li> 5386 <li>When the device implementation supports a secure lock screen and has a 5387 secure hardware such as a Secure Element (SE) where a Trusted Execution 5388 Environment (TEE) can be implemented, then it: 5389 <ul> 5390 <li>Is STRONGLY RECOMMENDED to back up the keystore implementation with the 5391 secure hardware. The upstream Android Open Source Project provides the 5392 Keymaster Hardware Abstraction Layer (HAL) implementation that can be used 5393 to satisfy this requirement.</li> 5394 <li>MUST perform the lock screen authentication in the secure hardware if 5395 the device has a hardware-backed keystore implementation and only when 5396 successful allow the authentication-bound keys to be used. The upstream 5397 Android Open Source Project provides the 5398 <a href="http://source.android.com/devices/tech/security/authentication/gatekeeper.html">Gatekeeper 5399 Hardware Abstraction Layer (HAL)</a> that can be used to satisfy this 5400 requirement.</li> 5401 </ul> 5402</li> 5403</ul> 5404 5405<p>Note that while the above TEE-related requirements are stated as STRONGLY 5406RECOMMENDED, the Compatibility Definition for the next API version is planned to 5407changed these to REQIUIRED. If a device implementation is already launched on an 5408earlier Android version and has not implemented a trusted operating system on 5409the secure hardware, such a device might not be able to meet the requirements 5410through a system software update and thus is STRONGLY RECOMMENDED to implement a 5411TEE.</p> 5412 5413<h2 id="9_12_data_deletion">9.12. Data Deletion</h2> 5414 5415<p>Devices MUST provide users with a mechanism to perform a "Factory Data Reset" 5416that allows logical and physical deletion of all data. This MUST satisfy 5417relevant industry standards for data deletion such as NIST SP800-88. This MUST 5418be used for the implementation of the wipeData() API (part of the Android Device 5419Administration API) described in <a href="#3_9_device_administration">section 54203.9 Device Administration</a>.</p> 5421 5422<p>Devices MAY provide a fast data wipe that conducts a logical data erase.</p> 5423 5424<h1 id="10_software_compatibility_testing">10. Software Compatibility 5425Testing</h1> 5426 5427 5428<p>Device implementations MUST pass all tests described in this section.</p> 5429 5430<p>However, note that no software test package is fully comprehensive. For this 5431reason, device implementers are <strong>STRONGLY RECOMMENDED</strong> to make 5432the minimum number of changes as possible to the reference and preferred 5433implementation of Android available from the Android Open Source Project. This 5434will minimize the risk of introducing bugs that create incompatibilities 5435requiring rework and potential device updates.</p> 5436 5437<h2 id="10_1_compatibility_test_suite">10.1. Compatibility Test Suite</h2> 5438 5439 5440<p>Device implementations MUST pass the 5441<a href="http://source.android.com/compatibility/index.html">Android 5442Compatibility Test Suite (CTS)</a> available from the Android Open Source 5443Project, using the final shipping software on the device. Additionally, device 5444implementers SHOULD use the reference implementation in the Android Open Source 5445tree as much as possible, and MUST ensure compatibility in cases of ambiguity in 5446CTS and for any reimplementations of parts of the reference source code.</p> 5447 5448<p>The CTS is designed to be run on an actual device. Like any software, the CTS 5449may itself contain bugs. The CTS will be versioned independently of this 5450Compatibility Definition, and multiple revisions of the CTS may be released for 5451Android ANDROID_VERSION. Device implementations MUST pass the latest CTS version 5452available at the time the device software is completed.</p> 5453 5454<h2 id="10_2_cts_verifier">10.2. CTS Verifier</h2> 5455 5456 5457<p>Device implementations MUST correctly execute all applicable cases in the CTS 5458Verifier. The CTS Verifier is included with the Compatibility Test Suite, and 5459is intended to be run by a human operator to test functionality that cannot be 5460tested by an automated system, such as correct functioning of a camera and 5461sensors.</p> 5462 5463<p>The CTS Verifier has tests for many kinds of hardware, including some 5464hardware that is optional. Device implementations MUST pass all tests for 5465hardware that they possess; for instance, if a device possesses an 5466accelerometer, it MUST correctly execute the Accelerometer test case in the CTS 5467Verifier. Test cases for features noted as optional by this Compatibility 5468Definition Document MAY be skipped or omitted.</p> 5469 5470<p>Every device and every build MUST correctly run the CTS Verifier, as noted 5471above. However, since many builds are very similar, device implementers are not 5472expected to explicitly run the CTS Verifier on builds that differ only in 5473trivial ways. Specifically, device implementations that differ from an 5474implementation that has passed the CTS Verifier only by the set of included 5475locales, branding, etc. MAY omit the CTS Verifier test.</p> 5476 5477<h1 id="11_updatable_software">11. Updatable Software</h1> 5478 5479 5480<p>Device implementations MUST include a mechanism to replace the entirety of 5481the system software. The mechanism need not perform “live” 5482upgrades—that is, a device restart MAY be required.</p> 5483 5484<p>Any method can be used, provided that it can replace the entirety of the 5485software preinstalled on the device. For instance, any of the following 5486approaches will satisfy this requirement:</p> 5487 5488<ul> 5489 <li>“Over-the-air (OTA)” downloads with offline update via 5490 reboot.</li> 5491 <li>“Tethered” updates over USB from a host PC.</li> 5492 <li>“Offline” updates via a reboot and update from a file on 5493 removable storage.</li> 5494</ul> 5495 5496<p>However, if the device implementation includes support for an unmetered data 5497connection such as 802.11 or Bluetooth PAN (Personal Area Network) profile:</p> 5498 5499<ul> 5500 <li>Android Automotive implementations SHOULD support OTA downloads with 5501 offline update via reboot.</li> 5502 <li>All other device implementations MUST support OTA downloads with offline 5503 update via reboot.</li> 5504</ul> 5505 5506<p>The update mechanism used MUST support updates without wiping user data. That 5507is, the update mechanism MUST preserve application private data and application 5508shared data. Note that the upstream Android software includes an update 5509mechanism that satisfies this requirement.</p> 5510 5511<p>For device implementations that are launching with Android ANDROID_VERSION 5512and later, the update mechanism SHOULD support verifying that the system image 5513is binary identical to expected result following an OTA. The block-based OTA 5514implementation in the upstream Android Open Source Project, added since Android 55155.1, satisfies this requirement.</p> 5516 5517<p>If an error is found in a device implementation after it has been released 5518but within its reasonable product lifetime that is determined in consultation 5519with the Android Compatibility Team to affect the compatibility of third-party 5520applications, the device implementer MUST correct the error via a software 5521update available that can be applied per the mechanism just described.</p> 5522 5523<p>Android includes features that allow the Device Owner app (if present) to 5524control the installation of system updates. To facilitate this, the system 5525update subsystem for devices that report android.software.device_admin MUST 5526implement the behavior described in the 5527<a href="http://developer.android.com/reference/android/app/admin/SystemUpdatePolicy.html">SystemUpdatePolicy</a> 5528class.</p> 5529 5530<h1 id="12_document_changelog">12. Document Changelog</h1> 5531 5532<p>For a summary of changes to the Compatibility Definition in this release, 5533refer to the <a href="https://android.googlesource.com/platform/docs/source.android.com/+log/master/src/compatibility">changelog</a>. 5534</p> 5535 5536<h1 id="13_contact_us">13. Contact Us</h1> 5537 5538 5539<p>You can join the 5540<a href="https://groups.google.com/forum/#!forum/android-compatibility">android-compatibility 5541forum</a> and ask for clarifications or bring up any issues that you think the 5542document does not cover.</p> 5543 5544</div> 5545</body> 5546</html> 5547
