## 3.2\. Soft API Compatibility In addition to the managed APIs from [section 3.1](#3_1_managed_api_compatibility), Android also includes a significant runtime-only “soft” API, in the form of such things as intents, permissions, and similar aspects of Android applications that cannot be enforced at application compile time. ### 3.2.1\. Permissions * [C-0-1] Device implementers MUST support and enforce all permission constants as documented by the [Permission reference page](http://developer.android.com/reference/android/Manifest.permission.html). Note that [section 9](#9_security_model_compatibility) lists additional requirements related to the Android security model. ### 3.2.2\. Build Parameters The Android APIs include a number of constants on the [android.os.Build class](http://developer.android.com/reference/android/os/Build.html) that are intended to describe the current device. * [C-0-1] To provide consistent, meaningful values across device implementations, the table below includes additional restrictions on the formats of these values to which device implementations MUST conform.
Parameter Details
VERSION.RELEASE The version of the currently-executing Android system, in human-readable format. This field MUST have one of the string values defined in ANDROID_VERSION.
VERSION.SDK The version of the currently-executing Android system, in a format accessible to third-party application code. For Android ANDROID_VERSION, this field MUST have the integer value ANDROID_VERSION_INT.
VERSION.SDK_INT The version of the currently-executing Android system, in a format accessible to third-party application code. For Android ANDROID_VERSION, this field MUST have the integer value ANDROID_VERSION_INT.
VERSION.INCREMENTAL A value chosen by the device implementer designating the specific build of the currently-executing Android system, in human-readable format. This value MUST NOT be reused for different builds made available to end users. A typical use of this field is to indicate which build number or source-control change identifier was used to generate the build. There are no requirements on the specific format of this field, except that it MUST NOT be null or the empty string ("").
BOARD A value chosen by the device implementer identifying the specific internal hardware used by the device, in human-readable format. A possible use of this field is to indicate the specific revision of the board powering the device. The value of this field MUST be encodable as 7-bit ASCII and match the regular expression “^[a-zA-Z0-9_-]+$”.
BRAND A value reflecting the brand name associated with the device as known to the end users. MUST be in human-readable format and SHOULD represent the manufacturer of the device or the company brand under which the device is marketed. The value of this field MUST be encodable as 7-bit ASCII and match the regular expression “^[a-zA-Z0-9_-]+$”.
SUPPORTED_ABIS The name of the instruction set (CPU type + ABI convention) of native code. See section 3.3. Native API Compatibility.
SUPPORTED_32_BIT_ABIS The name of the instruction set (CPU type + ABI convention) of native code. See section 3.3. Native API Compatibility.
SUPPORTED_64_BIT_ABIS The name of the second instruction set (CPU type + ABI convention) of native code. See section 3.3. Native API Compatibility.
CPU_ABI The name of the instruction set (CPU type + ABI convention) of native code. See section 3.3. Native API Compatibility.
CPU_ABI2 The name of the second instruction set (CPU type + ABI convention) of native code. See section 3.3. Native API Compatibility.
DEVICE A value chosen by the device implementer containing the development name or code name identifying the configuration of the hardware features and industrial design of the device. The value of this field MUST be encodable as 7-bit ASCII and match the regular expression “^[a-zA-Z0-9_-]+$”. This device name MUST NOT change during the lifetime of the product.
FINGERPRINT A string that uniquely identifies this build. It SHOULD be reasonably human-readable. It MUST follow this template:

$(BRAND)/$(PRODUCT)/
    $(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)

For example:

acme/myproduct/
    mydevice:ANDROID_VERSION/LMYXX/3359:userdebug/test-keys

The fingerprint MUST NOT include whitespace characters. If other fields included in the template above have whitespace characters, they MUST be replaced in the build fingerprint with another character, such as the underscore ("_") character. The value of this field MUST be encodable as 7-bit ASCII.
HARDWARE The name of the hardware (from the kernel command line or /proc). It SHOULD be reasonably human-readable. The value of this field MUST be encodable as 7-bit ASCII and match the regular expression “^[a-zA-Z0-9_-]+$”.
HOST A string that uniquely identifies the host the build was built on, in human-readable format. There are no requirements on the specific format of this field, except that it MUST NOT be null or the empty string ("").
ID An identifier chosen by the device implementer to refer to a specific release, in human-readable format. This field can be the same as android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently meaningful for end users to distinguish between software builds. The value of this field MUST be encodable as 7-bit ASCII and match the regular expression “^[a-zA-Z0-9._-]+$”.
MANUFACTURER The trade name of the Original Equipment Manufacturer (OEM) of the product. There are no requirements on the specific format of this field, except that it MUST NOT be null or the empty string (""). This field MUST NOT change during the lifetime of the product.
MODEL A value chosen by the device implementer containing the name of the device as known to the end user. This SHOULD be the same name under which the device is marketed and sold to end users. There are no requirements on the specific format of this field, except that it MUST NOT be null or the empty string (""). This field MUST NOT change during the lifetime of the product.
PRODUCT A value chosen by the device implementer containing the development name or code name of the specific product (SKU) that MUST be unique within the same brand. MUST be human-readable, but is not necessarily intended for view by end users. The value of this field MUST be encodable as 7-bit ASCII and match the regular expression “^[a-zA-Z0-9_-]+$”. This product name MUST NOT change during the lifetime of the product.
SERIAL A hardware serial number, which MUST be available and unique across devices with the same MODEL and MANUFACTURER. The value of this field MUST be encodable as 7-bit ASCII and match the regular expression “^([a-zA-Z0-9]{6,20})$”.
TAGS A comma-separated list of tags chosen by the device implementer that further distinguishes the build. This field MUST have one of the values corresponding to the three typical Android platform signing configurations: release-keys, dev-keys, test-keys.
TIME A value representing the timestamp of when the build occurred.
TYPE A value chosen by the device implementer specifying the runtime configuration of the build. This field MUST have one of the values corresponding to the three typical Android runtime configurations: user, userdebug, or eng.
USER A name or user ID of the user (or automated user) that generated the build. There are no requirements on the specific format of this field, except that it MUST NOT be null or the empty string ("").
SECURITY_PATCH A value indicating the security patch level of a build. It MUST signify that the build is not in any way vulnerable to any of the issues described up through the designated Android Public Security Bulletin. It MUST be in the format [YYYY-MM-DD], matching a defined string documented in the Android Public Security Bulletin or in the Android Security Advisory, for example "2015-11-01".
BASE_OS A value representing the FINGERPRINT parameter of the build that is otherwise identical to this build except for the patches provided in the Android Public Security Bulletin. It MUST report the correct value and if such a build does not exist, report an empty string ("").
BOOTLOADER A value chosen by the device implementer identifying the specific internal bootloader version used in the device, in human-readable format. The value of this field MUST be encodable as 7-bit ASCII and match the regular expression “^[a-zA-Z0-9._-]+$”.
getRadioVersion() MUST (be or return) a value chosen by the device implementer identifying the specific internal radio/modem version used in the device, in human-readable format. If a device does not have any internal radio/modem it MUST return NULL. The value of this field MUST be encodable as 7-bit ASCII and match the regular expression “^[a-zA-Z0-9._-,]+$”.
### 3.2.3\. Intent Compatibility #### 3.2.3.1\. Core Application Intents Android intents allow application components to request functionality from other Android components. The Android upstream project includes a list of applications considered core Android applications, which implements several intent patterns to perform common actions. * [C-0-1] Device implementations MUST include these application, service components, or at least a handler, for all the public intent filter patterns defined by the the following core Android applications in AOSP: * Desk Clock * Browser * Calendar * Contacts * Gallery * GlobalSearch * Launcher * Music * Settings #### 3.2.3.2\. Intent Resolution * [C-0-1] As Android is an extensible platform, device implementations MUST allow each intent pattern referenced in [section 3.2.3.1](#3_2_3_1_core_application_intents) to be overridden by third-party applications. The upstream Android open source implementation allows this by default. * [C-0-2] Dvice implementers MUST NOT attach special privileges to system applications' use of these intent patterns, or prevent third-party applications from binding to and assuming control of these patterns. This prohibition specifically includes but is not limited to disabling the “Chooser” user interface that allows the user to select between multiple applications that all handle the same intent pattern. * [C-0-3] Device implementations MUST provide a user interface for users to modify the default activity for intents. * However, device implementations MAY provide default activities for specific URI patterns (e.g. http://play.google.com) when the default activity provides a more specific attribute for the data URI. For example, an intent filter pattern specifying the data URI “http://www.android.com” is more specific than the browser's core intent pattern for “http://”. Android also includes a mechanism for third-party apps to declare an authoritative default [app linking behavior](https://developer.android.com/training/app-links) for certain types of web URI intents. When such authoritative declarations are defined in an app's intent filter patterns, device implementations: * [C-0-4] MUST attempt to validate any intent filters by performing the validation steps defined in the [Digital Asset Links specification](https://developers.google.com/digital-asset-links) as implemented by the Package Manager in the upstream Android Open Source Project. * [C-0-5] MUST attempt validation of the intent filters during the installation of the application and set all successfully validated UIR intent filters as default app handlers for their UIRs. * MAY set specific URI intent filters as default app handlers for their URIs, if they are successfully verified but other candidate URI filters fail verification. If a device implementation does this, it MUST provide the user appropriate per-URI pattern overrides in the settings menu. * MUST provide the user with per-app App Links controls in Settings as follows: * [C-0-6] The user MUST be able to override holistically the default app links behavior for an app to be: always open, always ask, or never open, which must apply to all candidate URI intent filters equally. * [C-0-7] The user MUST be able to see a list of the candidate URI intent filters. * The device implementation MAY provide the user with the ability to override specific candidate URI intent filters that were successfully verified, on a per-intent filter basis. * [C-0-8] The device implementation MUST provide users with the ability to view and override specific candidate URI intent filters if the device implementation lets some candidate URI intent filters succeed verification while some others can fail. #### 3.2.3.3\. Intent Namespaces * [C-0-1] Device implementations MUST NOT include any Android component that honors any new intent or broadcast intent patterns using an ACTION, CATEGORY, or other key string in the android.* or com.android.* namespace. * [C-0-2] Device implementers MUST NOT include any Android components that honor any new intent or broadcast intent patterns using an ACTION, CATEGORY, or other key string in a package space belonging to another organization. * [C-0-3] Device implementers MUST NOT alter or extend any of the intent patterns used by the core apps listed in [section 3.2.3.1](#3_2_3_1_core_application_intents). * Device implementations MAY include intent patterns using namespaces clearly and obviously associated with their own organization. This prohibition is analogous to that specified for Java language classes in [section 3.6](#3_6_api_namespaces). #### 3.2.3.4\. Broadcast Intents Third-party applications rely on the platform to broadcast certain intents to notify them of changes in the hardware or software environment. Device implementations: * [C-0-1] MUST broadcast the public broadcast intents in response to appropriate system events as described in the SDK documentation. Note that this requirement is not conflicting with section 3.5 as the limitation for background applications are also described in the SDK documentation. #### 3.2.3.5\. Default App Settings Android includes settings that provide users an easy way to select their default applications, for example for Home screen or SMS. Where it makes sense, device implementations MUST provide a similar settings menu and be compatible with the intent filter pattern and API methods described in the SDK documentation as below. If device implementations report `android.software.home_screen`, they: * [C-1-1] MUST honor the [android.settings.HOME_SETTINGS]( http://developer.android.com/reference/android/provider/Settings.html#ACTION_HOME_SETTINGS) intent to show a default app settings menu for Home Screen. If device implementations report `android.hardware.telephony`, they: * [C-2-1] MUST provide a settings menu that will call the [android.provider.Telephony.ACTION_CHANGE_DEFAULT]( http://developer.android.com/reference/android/provider/Telephony.Sms.Intents.html) intent to show a dialog to change the default SMS application. If device implementations report `android.hardware.nfc.hce`, they: * [C-3-1] MUST honor the [android.settings.NFC_PAYMENT_SETTINGS]( http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFC_PAYMENT_SETTINGS) intent to show a default app settings menu for Tap and Pay. If device implementations report `android.hardware.telephony`, they: * [C-4-1] MUST honor the [android.telecom.action.CHANGE_DEFAULT_DIALER]( https://developer.android.com/reference/android/telecom/TelecomManager.html#ACTION_CHANGE_DEFAULT_DIALER) intent to show a dialog to allow the user to change the default Phone application. If device implementations support the VoiceInteractionService, they: * [C-5-1] MUST honor the [android.settings.ACTION_VOICE_INPUT_SETTINGS]( https://developer.android.com/reference/android/provider/Settings.html#ACTION_VOICE_INPUT_SETTINGS) intent to show a default app settings menu for voice input and assist. ### 3.2.4\. Activities on secondary displays If device implementations allow launching normal [Android Activities]( https://developer.android.com/reference/android/app/Activity.html) on secondary displays, they: * [C-1-1] MUST set the `android.software.activities_on_secondary_displays` feature flag. * [C-1-2] MUST guarantee API compatibility similar to an activity running on the primary display. * [C-1-3] MUST land the new activity on the same display as the activity that launched it, when the new activity is launched without specifying a target display via the [`ActivityOptions.setLaunchDisplayId()`]( https://developer.android.com/reference/android/app/ActivityOptions.html#setLaunchDisplayId%28int%29) API. * [C-1-4] MUST destory all activities, when a display with the [`Display.FLAG_PRIVATE`](http://developer.android.com/reference/android/view/Display.html#FLAG_PRIVATE) flag is removed. * [C-1-5] MUST resize accordingly all activities on a [`VirtualDisplay`]( https://developer.android.com/reference/android/hardware/display/VirtualDisplay.html) if the display itself is resized. * MAY show an IME (input method editor, a user control that enables users to enter text) on the primary display, when a text input field becomes focused on a secondary display. * SHOULD implement the input focus on the secondary display independently of the primary display, when touch or key inputs are supported. * SHOULD have [`android.content.res.Configuration`]( https://developer.android.com/reference/android/content/res/Configuration.html) which corresponds to that display in order to be displayed, operate correctly, and maintain compatibility if an activity is launched on secondary display. If device implementations allow launching normal [Android Activities]( https://developer.android.com/reference/android/app/Activity.html) on secondary displays and primary and secondary displays have different [android.util.DisplayMetrics](https://developer.android.com/reference/android/util/DisplayMetrics.html): * [C-2-1] Non-resizeable activities (that have `resizeableActivity=false` in `AndroidManifest.xml`) and apps targeting API level 23 or lower MUST NOT be allowed on secondary displays. If device implementations allow launching normal [Android Activities]( https://developer.android.com/reference/android/app/Activity.html) on secondary displays and a secondary display has the [android.view.Display.FLAG_PRIVATE]( https://developer.android.com/reference/android/view/Display.html#FLAG_PRIVATE) flag: * [C-3-1] Only the owner of that display, system, and activities that are already on that display MUST be able to launch to it. Everyone can launch to a display that has [android.view.Display.FLAG_PUBLIC](https://developer.android.com/reference/android/view/Display.html#FLAG_PUBLIC) flag.