1 /* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.app; 18 19 import static android.content.pm.ServiceInfo.FOREGROUND_SERVICE_TYPE_MANIFEST; 20 21 import android.annotation.IntDef; 22 import android.annotation.NonNull; 23 import android.annotation.Nullable; 24 import android.annotation.UnsupportedAppUsage; 25 import android.content.ComponentCallbacks2; 26 import android.content.ComponentName; 27 import android.content.Context; 28 import android.content.ContextWrapper; 29 import android.content.Intent; 30 import android.content.pm.ServiceInfo; 31 import android.content.pm.ServiceInfo.ForegroundServiceType; 32 import android.content.res.Configuration; 33 import android.os.Build; 34 import android.os.IBinder; 35 import android.os.RemoteException; 36 import android.util.Log; 37 38 import java.io.FileDescriptor; 39 import java.io.PrintWriter; 40 import java.lang.annotation.Retention; 41 import java.lang.annotation.RetentionPolicy; 42 43 /** 44 * A Service is an application component representing either an application's desire 45 * to perform a longer-running operation while not interacting with the user 46 * or to supply functionality for other applications to use. Each service 47 * class must have a corresponding 48 * {@link android.R.styleable#AndroidManifestService <service>} 49 * declaration in its package's <code>AndroidManifest.xml</code>. Services 50 * can be started with 51 * {@link android.content.Context#startService Context.startService()} and 52 * {@link android.content.Context#bindService Context.bindService()}. 53 * 54 * <p>Note that services, like other application objects, run in the main 55 * thread of their hosting process. This means that, if your service is going 56 * to do any CPU intensive (such as MP3 playback) or blocking (such as 57 * networking) operations, it should spawn its own thread in which to do that 58 * work. More information on this can be found in 59 * <a href="{@docRoot}guide/topics/fundamentals/processes-and-threads.html">Processes and 60 * Threads</a>. The {@link IntentService} class is available 61 * as a standard implementation of Service that has its own thread where it 62 * schedules its work to be done.</p> 63 * 64 * <p>Topics covered here: 65 * <ol> 66 * <li><a href="#WhatIsAService">What is a Service?</a> 67 * <li><a href="#ServiceLifecycle">Service Lifecycle</a> 68 * <li><a href="#Permissions">Permissions</a> 69 * <li><a href="#ProcessLifecycle">Process Lifecycle</a> 70 * <li><a href="#LocalServiceSample">Local Service Sample</a> 71 * <li><a href="#RemoteMessengerServiceSample">Remote Messenger Service Sample</a> 72 * </ol> 73 * 74 * <div class="special reference"> 75 * <h3>Developer Guides</h3> 76 * <p>For a detailed discussion about how to create services, read the 77 * <a href="{@docRoot}guide/topics/fundamentals/services.html">Services</a> developer guide.</p> 78 * </div> 79 * 80 * <a name="WhatIsAService"></a> 81 * <h3>What is a Service?</h3> 82 * 83 * <p>Most confusion about the Service class actually revolves around what 84 * it is <em>not</em>:</p> 85 * 86 * <ul> 87 * <li> A Service is <b>not</b> a separate process. The Service object itself 88 * does not imply it is running in its own process; unless otherwise specified, 89 * it runs in the same process as the application it is part of. 90 * <li> A Service is <b>not</b> a thread. It is not a means itself to do work off 91 * of the main thread (to avoid Application Not Responding errors). 92 * </ul> 93 * 94 * <p>Thus a Service itself is actually very simple, providing two main features:</p> 95 * 96 * <ul> 97 * <li>A facility for the application to tell the system <em>about</em> 98 * something it wants to be doing in the background (even when the user is not 99 * directly interacting with the application). This corresponds to calls to 100 * {@link android.content.Context#startService Context.startService()}, which 101 * ask the system to schedule work for the service, to be run until the service 102 * or someone else explicitly stop it. 103 * <li>A facility for an application to expose some of its functionality to 104 * other applications. This corresponds to calls to 105 * {@link android.content.Context#bindService Context.bindService()}, which 106 * allows a long-standing connection to be made to the service in order to 107 * interact with it. 108 * </ul> 109 * 110 * <p>When a Service component is actually created, for either of these reasons, 111 * all that the system actually does is instantiate the component 112 * and call its {@link #onCreate} and any other appropriate callbacks on the 113 * main thread. It is up to the Service to implement these with the appropriate 114 * behavior, such as creating a secondary thread in which it does its work.</p> 115 * 116 * <p>Note that because Service itself is so simple, you can make your 117 * interaction with it as simple or complicated as you want: from treating it 118 * as a local Java object that you make direct method calls on (as illustrated 119 * by <a href="#LocalServiceSample">Local Service Sample</a>), to providing 120 * a full remoteable interface using AIDL.</p> 121 * 122 * <a name="ServiceLifecycle"></a> 123 * <h3>Service Lifecycle</h3> 124 * 125 * <p>There are two reasons that a service can be run by the system. If someone 126 * calls {@link android.content.Context#startService Context.startService()} then the system will 127 * retrieve the service (creating it and calling its {@link #onCreate} method 128 * if needed) and then call its {@link #onStartCommand} method with the 129 * arguments supplied by the client. The service will at this point continue 130 * running until {@link android.content.Context#stopService Context.stopService()} or 131 * {@link #stopSelf()} is called. Note that multiple calls to 132 * Context.startService() do not nest (though they do result in multiple corresponding 133 * calls to onStartCommand()), so no matter how many times it is started a service 134 * will be stopped once Context.stopService() or stopSelf() is called; however, 135 * services can use their {@link #stopSelf(int)} method to ensure the service is 136 * not stopped until started intents have been processed. 137 * 138 * <p>For started services, there are two additional major modes of operation 139 * they can decide to run in, depending on the value they return from 140 * onStartCommand(): {@link #START_STICKY} is used for services that are 141 * explicitly started and stopped as needed, while {@link #START_NOT_STICKY} 142 * or {@link #START_REDELIVER_INTENT} are used for services that should only 143 * remain running while processing any commands sent to them. See the linked 144 * documentation for more detail on the semantics. 145 * 146 * <p>Clients can also use {@link android.content.Context#bindService Context.bindService()} to 147 * obtain a persistent connection to a service. This likewise creates the 148 * service if it is not already running (calling {@link #onCreate} while 149 * doing so), but does not call onStartCommand(). The client will receive the 150 * {@link android.os.IBinder} object that the service returns from its 151 * {@link #onBind} method, allowing the client to then make calls back 152 * to the service. The service will remain running as long as the connection 153 * is established (whether or not the client retains a reference on the 154 * service's IBinder). Usually the IBinder returned is for a complex 155 * interface that has been <a href="{@docRoot}guide/components/aidl.html">written 156 * in aidl</a>. 157 * 158 * <p>A service can be both started and have connections bound to it. In such 159 * a case, the system will keep the service running as long as either it is 160 * started <em>or</em> there are one or more connections to it with the 161 * {@link android.content.Context#BIND_AUTO_CREATE Context.BIND_AUTO_CREATE} 162 * flag. Once neither 163 * of these situations hold, the service's {@link #onDestroy} method is called 164 * and the service is effectively terminated. All cleanup (stopping threads, 165 * unregistering receivers) should be complete upon returning from onDestroy(). 166 * 167 * <a name="Permissions"></a> 168 * <h3>Permissions</h3> 169 * 170 * <p>Global access to a service can be enforced when it is declared in its 171 * manifest's {@link android.R.styleable#AndroidManifestService <service>} 172 * tag. By doing so, other applications will need to declare a corresponding 173 * {@link android.R.styleable#AndroidManifestUsesPermission <uses-permission>} 174 * element in their own manifest to be able to start, stop, or bind to 175 * the service. 176 * 177 * <p>As of {@link android.os.Build.VERSION_CODES#GINGERBREAD}, when using 178 * {@link Context#startService(Intent) Context.startService(Intent)}, you can 179 * also set {@link Intent#FLAG_GRANT_READ_URI_PERMISSION 180 * Intent.FLAG_GRANT_READ_URI_PERMISSION} and/or {@link Intent#FLAG_GRANT_WRITE_URI_PERMISSION 181 * Intent.FLAG_GRANT_WRITE_URI_PERMISSION} on the Intent. This will grant the 182 * Service temporary access to the specific URIs in the Intent. Access will 183 * remain until the Service has called {@link #stopSelf(int)} for that start 184 * command or a later one, or until the Service has been completely stopped. 185 * This works for granting access to the other apps that have not requested 186 * the permission protecting the Service, or even when the Service is not 187 * exported at all. 188 * 189 * <p>In addition, a service can protect individual IPC calls into it with 190 * permissions, by calling the 191 * {@link #checkCallingPermission} 192 * method before executing the implementation of that call. 193 * 194 * <p>See the <a href="{@docRoot}guide/topics/security/security.html">Security and Permissions</a> 195 * document for more information on permissions and security in general. 196 * 197 * <a name="ProcessLifecycle"></a> 198 * <h3>Process Lifecycle</h3> 199 * 200 * <p>The Android system will attempt to keep the process hosting a service 201 * around as long as the service has been started or has clients bound to it. 202 * When running low on memory and needing to kill existing processes, the 203 * priority of a process hosting the service will be the higher of the 204 * following possibilities: 205 * 206 * <ul> 207 * <li><p>If the service is currently executing code in its 208 * {@link #onCreate onCreate()}, {@link #onStartCommand onStartCommand()}, 209 * or {@link #onDestroy onDestroy()} methods, then the hosting process will 210 * be a foreground process to ensure this code can execute without 211 * being killed. 212 * <li><p>If the service has been started, then its hosting process is considered 213 * to be less important than any processes that are currently visible to the 214 * user on-screen, but more important than any process not visible. Because 215 * only a few processes are generally visible to the user, this means that 216 * the service should not be killed except in low memory conditions. However, since 217 * the user is not directly aware of a background service, in that state it <em>is</em> 218 * considered a valid candidate to kill, and you should be prepared for this to 219 * happen. In particular, long-running services will be increasingly likely to 220 * kill and are guaranteed to be killed (and restarted if appropriate) if they 221 * remain started long enough. 222 * <li><p>If there are clients bound to the service, then the service's hosting 223 * process is never less important than the most important client. That is, 224 * if one of its clients is visible to the user, then the service itself is 225 * considered to be visible. The way a client's importance impacts the service's 226 * importance can be adjusted through {@link Context#BIND_ABOVE_CLIENT}, 227 * {@link Context#BIND_ALLOW_OOM_MANAGEMENT}, {@link Context#BIND_WAIVE_PRIORITY}, 228 * {@link Context#BIND_IMPORTANT}, and {@link Context#BIND_ADJUST_WITH_ACTIVITY}. 229 * <li><p>A started service can use the {@link #startForeground(int, Notification)} 230 * API to put the service in a foreground state, where the system considers 231 * it to be something the user is actively aware of and thus not a candidate 232 * for killing when low on memory. (It is still theoretically possible for 233 * the service to be killed under extreme memory pressure from the current 234 * foreground application, but in practice this should not be a concern.) 235 * </ul> 236 * 237 * <p>Note this means that most of the time your service is running, it may 238 * be killed by the system if it is under heavy memory pressure. If this 239 * happens, the system will later try to restart the service. An important 240 * consequence of this is that if you implement {@link #onStartCommand onStartCommand()} 241 * to schedule work to be done asynchronously or in another thread, then you 242 * may want to use {@link #START_FLAG_REDELIVERY} to have the system 243 * re-deliver an Intent for you so that it does not get lost if your service 244 * is killed while processing it. 245 * 246 * <p>Other application components running in the same process as the service 247 * (such as an {@link android.app.Activity}) can, of course, increase the 248 * importance of the overall 249 * process beyond just the importance of the service itself. 250 * 251 * <a name="LocalServiceSample"></a> 252 * <h3>Local Service Sample</h3> 253 * 254 * <p>One of the most common uses of a Service is as a secondary component 255 * running alongside other parts of an application, in the same process as 256 * the rest of the components. All components of an .apk run in the same 257 * process unless explicitly stated otherwise, so this is a typical situation. 258 * 259 * <p>When used in this way, by assuming the 260 * components are in the same process, you can greatly simplify the interaction 261 * between them: clients of the service can simply cast the IBinder they 262 * receive from it to a concrete class published by the service. 263 * 264 * <p>An example of this use of a Service is shown here. First is the Service 265 * itself, publishing a custom class when bound: 266 * 267 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/LocalService.java 268 * service} 269 * 270 * <p>With that done, one can now write client code that directly accesses the 271 * running service, such as: 272 * 273 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/LocalServiceActivities.java 274 * bind} 275 * 276 * <a name="RemoteMessengerServiceSample"></a> 277 * <h3>Remote Messenger Service Sample</h3> 278 * 279 * <p>If you need to be able to write a Service that can perform complicated 280 * communication with clients in remote processes (beyond simply the use of 281 * {@link Context#startService(Intent) Context.startService} to send 282 * commands to it), then you can use the {@link android.os.Messenger} class 283 * instead of writing full AIDL files. 284 * 285 * <p>An example of a Service that uses Messenger as its client interface 286 * is shown here. First is the Service itself, publishing a Messenger to 287 * an internal Handler when bound: 288 * 289 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/MessengerService.java 290 * service} 291 * 292 * <p>If we want to make this service run in a remote process (instead of the 293 * standard one for its .apk), we can use <code>android:process</code> in its 294 * manifest tag to specify one: 295 * 296 * {@sample development/samples/ApiDemos/AndroidManifest.xml remote_service_declaration} 297 * 298 * <p>Note that the name "remote" chosen here is arbitrary, and you can use 299 * other names if you want additional processes. The ':' prefix appends the 300 * name to your package's standard process name. 301 * 302 * <p>With that done, clients can now bind to the service and send messages 303 * to it. Note that this allows clients to register with it to receive 304 * messages back as well: 305 * 306 * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/MessengerServiceActivities.java 307 * bind} 308 */ 309 public abstract class Service extends ContextWrapper implements ComponentCallbacks2 { 310 private static final String TAG = "Service"; 311 312 /** 313 * Flag for {@link #stopForeground(int)}: if set, the notification previously provided 314 * to {@link #startForeground} will be removed. Otherwise it will remain 315 * until a later call (to {@link #startForeground(int, Notification)} or 316 * {@link #stopForeground(int)} removes it, or the service is destroyed. 317 */ 318 public static final int STOP_FOREGROUND_REMOVE = 1<<0; 319 320 /** 321 * Flag for {@link #stopForeground(int)}: if set, the notification previously provided 322 * to {@link #startForeground} will be detached from the service. Only makes sense 323 * when {@link #STOP_FOREGROUND_REMOVE} is <b>not</b> set -- in this case, the notification 324 * will remain shown, but be completely detached from the service and so no longer changed 325 * except through direct calls to the notification manager. 326 */ 327 public static final int STOP_FOREGROUND_DETACH = 1<<1; 328 329 /** @hide */ 330 @IntDef(flag = true, prefix = { "STOP_FOREGROUND_" }, value = { 331 STOP_FOREGROUND_REMOVE, 332 STOP_FOREGROUND_DETACH 333 }) 334 @Retention(RetentionPolicy.SOURCE) 335 public @interface StopForegroundFlags {} 336 Service()337 public Service() { 338 super(null); 339 } 340 341 /** Return the application that owns this service. */ getApplication()342 public final Application getApplication() { 343 return mApplication; 344 } 345 346 /** 347 * Called by the system when the service is first created. Do not call this method directly. 348 */ onCreate()349 public void onCreate() { 350 } 351 352 /** 353 * @deprecated Implement {@link #onStartCommand(Intent, int, int)} instead. 354 */ 355 @Deprecated onStart(Intent intent, int startId)356 public void onStart(Intent intent, int startId) { 357 } 358 359 /** 360 * Bits returned by {@link #onStartCommand} describing how to continue 361 * the service if it is killed. May be {@link #START_STICKY}, 362 * {@link #START_NOT_STICKY}, {@link #START_REDELIVER_INTENT}, 363 * or {@link #START_STICKY_COMPATIBILITY}. 364 */ 365 public static final int START_CONTINUATION_MASK = 0xf; 366 367 /** 368 * Constant to return from {@link #onStartCommand}: compatibility 369 * version of {@link #START_STICKY} that does not guarantee that 370 * {@link #onStartCommand} will be called again after being killed. 371 */ 372 public static final int START_STICKY_COMPATIBILITY = 0; 373 374 /** 375 * Constant to return from {@link #onStartCommand}: if this service's 376 * process is killed while it is started (after returning from 377 * {@link #onStartCommand}), then leave it in the started state but 378 * don't retain this delivered intent. Later the system will try to 379 * re-create the service. Because it is in the started state, it will 380 * guarantee to call {@link #onStartCommand} after creating the new 381 * service instance; if there are not any pending start commands to be 382 * delivered to the service, it will be called with a null intent 383 * object, so you must take care to check for this. 384 * 385 * <p>This mode makes sense for things that will be explicitly started 386 * and stopped to run for arbitrary periods of time, such as a service 387 * performing background music playback. 388 */ 389 public static final int START_STICKY = 1; 390 391 /** 392 * Constant to return from {@link #onStartCommand}: if this service's 393 * process is killed while it is started (after returning from 394 * {@link #onStartCommand}), and there are no new start intents to 395 * deliver to it, then take the service out of the started state and 396 * don't recreate until a future explicit call to 397 * {@link Context#startService Context.startService(Intent)}. The 398 * service will not receive a {@link #onStartCommand(Intent, int, int)} 399 * call with a null Intent because it will not be restarted if there 400 * are no pending Intents to deliver. 401 * 402 * <p>This mode makes sense for things that want to do some work as a 403 * result of being started, but can be stopped when under memory pressure 404 * and will explicit start themselves again later to do more work. An 405 * example of such a service would be one that polls for data from 406 * a server: it could schedule an alarm to poll every N minutes by having 407 * the alarm start its service. When its {@link #onStartCommand} is 408 * called from the alarm, it schedules a new alarm for N minutes later, 409 * and spawns a thread to do its networking. If its process is killed 410 * while doing that check, the service will not be restarted until the 411 * alarm goes off. 412 */ 413 public static final int START_NOT_STICKY = 2; 414 415 /** 416 * Constant to return from {@link #onStartCommand}: if this service's 417 * process is killed while it is started (after returning from 418 * {@link #onStartCommand}), then it will be scheduled for a restart 419 * and the last delivered Intent re-delivered to it again via 420 * {@link #onStartCommand}. This Intent will remain scheduled for 421 * redelivery until the service calls {@link #stopSelf(int)} with the 422 * start ID provided to {@link #onStartCommand}. The 423 * service will not receive a {@link #onStartCommand(Intent, int, int)} 424 * call with a null Intent because it will only be restarted if 425 * it is not finished processing all Intents sent to it (and any such 426 * pending events will be delivered at the point of restart). 427 */ 428 public static final int START_REDELIVER_INTENT = 3; 429 430 /** @hide */ 431 @IntDef(flag = false, prefix = { "START_" }, value = { 432 START_STICKY_COMPATIBILITY, 433 START_STICKY, 434 START_NOT_STICKY, 435 START_REDELIVER_INTENT, 436 }) 437 @Retention(RetentionPolicy.SOURCE) 438 public @interface StartResult {} 439 440 /** 441 * Special constant for reporting that we are done processing 442 * {@link #onTaskRemoved(Intent)}. 443 * @hide 444 */ 445 public static final int START_TASK_REMOVED_COMPLETE = 1000; 446 447 /** 448 * This flag is set in {@link #onStartCommand} if the Intent is a 449 * re-delivery of a previously delivered intent, because the service 450 * had previously returned {@link #START_REDELIVER_INTENT} but had been 451 * killed before calling {@link #stopSelf(int)} for that Intent. 452 */ 453 public static final int START_FLAG_REDELIVERY = 0x0001; 454 455 /** 456 * This flag is set in {@link #onStartCommand} if the Intent is a 457 * retry because the original attempt never got to or returned from 458 * {@link #onStartCommand(Intent, int, int)}. 459 */ 460 public static final int START_FLAG_RETRY = 0x0002; 461 462 /** @hide */ 463 @IntDef(flag = true, prefix = { "START_FLAG_" }, value = { 464 START_FLAG_REDELIVERY, 465 START_FLAG_RETRY, 466 }) 467 @Retention(RetentionPolicy.SOURCE) 468 public @interface StartArgFlags {} 469 470 471 /** 472 * Called by the system every time a client explicitly starts the service by calling 473 * {@link android.content.Context#startService}, providing the arguments it supplied and a 474 * unique integer token representing the start request. Do not call this method directly. 475 * 476 * <p>For backwards compatibility, the default implementation calls 477 * {@link #onStart} and returns either {@link #START_STICKY} 478 * or {@link #START_STICKY_COMPATIBILITY}. 479 * 480 * <p class="caution">Note that the system calls this on your 481 * service's main thread. A service's main thread is the same 482 * thread where UI operations take place for Activities running in the 483 * same process. You should always avoid stalling the main 484 * thread's event loop. When doing long-running operations, 485 * network calls, or heavy disk I/O, you should kick off a new 486 * thread, or use {@link android.os.AsyncTask}.</p> 487 * 488 * @param intent The Intent supplied to {@link android.content.Context#startService}, 489 * as given. This may be null if the service is being restarted after 490 * its process has gone away, and it had previously returned anything 491 * except {@link #START_STICKY_COMPATIBILITY}. 492 * @param flags Additional data about this start request. 493 * @param startId A unique integer representing this specific request to 494 * start. Use with {@link #stopSelfResult(int)}. 495 * 496 * @return The return value indicates what semantics the system should 497 * use for the service's current started state. It may be one of the 498 * constants associated with the {@link #START_CONTINUATION_MASK} bits. 499 * 500 * @see #stopSelfResult(int) 501 */ onStartCommand(Intent intent, @StartArgFlags int flags, int startId)502 public @StartResult int onStartCommand(Intent intent, @StartArgFlags int flags, int startId) { 503 onStart(intent, startId); 504 return mStartCompatibility ? START_STICKY_COMPATIBILITY : START_STICKY; 505 } 506 507 /** 508 * Called by the system to notify a Service that it is no longer used and is being removed. The 509 * service should clean up any resources it holds (threads, registered 510 * receivers, etc) at this point. Upon return, there will be no more calls 511 * in to this Service object and it is effectively dead. Do not call this method directly. 512 */ onDestroy()513 public void onDestroy() { 514 } 515 onConfigurationChanged(Configuration newConfig)516 public void onConfigurationChanged(Configuration newConfig) { 517 } 518 onLowMemory()519 public void onLowMemory() { 520 } 521 onTrimMemory(int level)522 public void onTrimMemory(int level) { 523 } 524 525 /** 526 * Return the communication channel to the service. May return null if 527 * clients can not bind to the service. The returned 528 * {@link android.os.IBinder} is usually for a complex interface 529 * that has been <a href="{@docRoot}guide/components/aidl.html">described using 530 * aidl</a>. 531 * 532 * <p><em>Note that unlike other application components, calls on to the 533 * IBinder interface returned here may not happen on the main thread 534 * of the process</em>. More information about the main thread can be found in 535 * <a href="{@docRoot}guide/topics/fundamentals/processes-and-threads.html">Processes and 536 * Threads</a>.</p> 537 * 538 * @param intent The Intent that was used to bind to this service, 539 * as given to {@link android.content.Context#bindService 540 * Context.bindService}. Note that any extras that were included with 541 * the Intent at that point will <em>not</em> be seen here. 542 * 543 * @return Return an IBinder through which clients can call on to the 544 * service. 545 */ 546 @Nullable onBind(Intent intent)547 public abstract IBinder onBind(Intent intent); 548 549 /** 550 * Called when all clients have disconnected from a particular interface 551 * published by the service. The default implementation does nothing and 552 * returns false. 553 * 554 * @param intent The Intent that was used to bind to this service, 555 * as given to {@link android.content.Context#bindService 556 * Context.bindService}. Note that any extras that were included with 557 * the Intent at that point will <em>not</em> be seen here. 558 * 559 * @return Return true if you would like to have the service's 560 * {@link #onRebind} method later called when new clients bind to it. 561 */ onUnbind(Intent intent)562 public boolean onUnbind(Intent intent) { 563 return false; 564 } 565 566 /** 567 * Called when new clients have connected to the service, after it had 568 * previously been notified that all had disconnected in its 569 * {@link #onUnbind}. This will only be called if the implementation 570 * of {@link #onUnbind} was overridden to return true. 571 * 572 * @param intent The Intent that was used to bind to this service, 573 * as given to {@link android.content.Context#bindService 574 * Context.bindService}. Note that any extras that were included with 575 * the Intent at that point will <em>not</em> be seen here. 576 */ onRebind(Intent intent)577 public void onRebind(Intent intent) { 578 } 579 580 /** 581 * This is called if the service is currently running and the user has 582 * removed a task that comes from the service's application. If you have 583 * set {@link android.content.pm.ServiceInfo#FLAG_STOP_WITH_TASK ServiceInfo.FLAG_STOP_WITH_TASK} 584 * then you will not receive this callback; instead, the service will simply 585 * be stopped. 586 * 587 * @param rootIntent The original root Intent that was used to launch 588 * the task that is being removed. 589 */ onTaskRemoved(Intent rootIntent)590 public void onTaskRemoved(Intent rootIntent) { 591 } 592 593 /** 594 * Stop the service, if it was previously started. This is the same as 595 * calling {@link android.content.Context#stopService} for this particular service. 596 * 597 * @see #stopSelfResult(int) 598 */ stopSelf()599 public final void stopSelf() { 600 stopSelf(-1); 601 } 602 603 /** 604 * Old version of {@link #stopSelfResult} that doesn't return a result. 605 * 606 * @see #stopSelfResult 607 */ stopSelf(int startId)608 public final void stopSelf(int startId) { 609 if (mActivityManager == null) { 610 return; 611 } 612 try { 613 mActivityManager.stopServiceToken( 614 new ComponentName(this, mClassName), mToken, startId); 615 } catch (RemoteException ex) { 616 } 617 } 618 619 /** 620 * Stop the service if the most recent time it was started was 621 * <var>startId</var>. This is the same as calling {@link 622 * android.content.Context#stopService} for this particular service but allows you to 623 * safely avoid stopping if there is a start request from a client that you 624 * haven't yet seen in {@link #onStart}. 625 * 626 * <p><em>Be careful about ordering of your calls to this function.</em>. 627 * If you call this function with the most-recently received ID before 628 * you have called it for previously received IDs, the service will be 629 * immediately stopped anyway. If you may end up processing IDs out 630 * of order (such as by dispatching them on separate threads), then you 631 * are responsible for stopping them in the same order you received them.</p> 632 * 633 * @param startId The most recent start identifier received in {@link 634 * #onStart}. 635 * @return Returns true if the startId matches the last start request 636 * and the service will be stopped, else false. 637 * 638 * @see #stopSelf() 639 */ stopSelfResult(int startId)640 public final boolean stopSelfResult(int startId) { 641 if (mActivityManager == null) { 642 return false; 643 } 644 try { 645 return mActivityManager.stopServiceToken( 646 new ComponentName(this, mClassName), mToken, startId); 647 } catch (RemoteException ex) { 648 } 649 return false; 650 } 651 652 /** 653 * @deprecated This is a now a no-op, use 654 * {@link #startForeground(int, Notification)} instead. This method 655 * has been turned into a no-op rather than simply being deprecated 656 * because analysis of numerous poorly behaving devices has shown that 657 * increasingly often the trouble is being caused in part by applications 658 * that are abusing it. Thus, given a choice between introducing 659 * problems in existing applications using this API (by allowing them to 660 * be killed when they would like to avoid it), vs allowing the performance 661 * of the entire system to be decreased, this method was deemed less 662 * important. 663 * 664 * @hide 665 */ 666 @Deprecated 667 @UnsupportedAppUsage setForeground(boolean isForeground)668 public final void setForeground(boolean isForeground) { 669 Log.w(TAG, "setForeground: ignoring old API call on " + getClass().getName()); 670 } 671 672 /** 673 * If your service is started (running through {@link Context#startService(Intent)}), then 674 * also make this service run in the foreground, supplying the ongoing 675 * notification to be shown to the user while in this state. 676 * By default started services are background, meaning that their process won't be given 677 * foreground CPU scheduling (unless something else in that process is foreground) and, 678 * if the system needs to kill them to reclaim more memory (such as to display a large page in a 679 * web browser), they can be killed without too much harm. You use 680 * {@link #startForeground} if killing your service would be disruptive to the user, such as 681 * if your service is performing background music playback, so the user 682 * would notice if their music stopped playing. 683 * 684 * <p>Note that calling this method does <em>not</em> put the service in the started state 685 * itself, even though the name sounds like it. You must always call 686 * {@link #startService(Intent)} first to tell the system it should keep the service running, 687 * and then use this method to tell it to keep it running harder.</p> 688 * 689 * <p>Apps targeting API {@link android.os.Build.VERSION_CODES#P} or later must request 690 * the permission {@link android.Manifest.permission#FOREGROUND_SERVICE} in order to use 691 * this API.</p> 692 * 693 * <p>Apps built with SDK version {@link android.os.Build.VERSION_CODES#Q} or later can specify 694 * the foreground service types using attribute {@link android.R.attr#foregroundServiceType} in 695 * service element of manifest file. The value of attribute 696 * {@link android.R.attr#foregroundServiceType} can be multiple flags ORed together.</p> 697 * 698 * @param id The identifier for this notification as per 699 * {@link NotificationManager#notify(int, Notification) 700 * NotificationManager.notify(int, Notification)}; must not be 0. 701 * @param notification The Notification to be displayed. 702 * 703 * @see #stopForeground(boolean) 704 */ startForeground(int id, Notification notification)705 public final void startForeground(int id, Notification notification) { 706 try { 707 mActivityManager.setServiceForeground( 708 new ComponentName(this, mClassName), mToken, id, 709 notification, 0, FOREGROUND_SERVICE_TYPE_MANIFEST); 710 } catch (RemoteException ex) { 711 } 712 } 713 714 /** 715 * An overloaded version of {@link #startForeground(int, Notification)} with additional 716 * foregroundServiceType parameter. 717 * 718 * <p>Apps built with SDK version {@link android.os.Build.VERSION_CODES#Q} or later can specify 719 * the foreground service types using attribute {@link android.R.attr#foregroundServiceType} in 720 * service element of manifest file. The value of attribute 721 * {@link android.R.attr#foregroundServiceType} can be multiple flags ORed together.</p> 722 * 723 * <p>The foregroundServiceType parameter must be a subset flags of what is specified in manifest 724 * attribute {@link android.R.attr#foregroundServiceType}, if not, an IllegalArgumentException is 725 * thrown. Specify foregroundServiceType parameter as 726 * {@link android.content.pm.ServiceInfo#FOREGROUND_SERVICE_TYPE_MANIFEST} to use all flags that 727 * is specified in manifest attribute foregroundServiceType.</p> 728 * 729 * @param id The identifier for this notification as per 730 * {@link NotificationManager#notify(int, Notification) 731 * NotificationManager.notify(int, Notification)}; must not be 0. 732 * @param notification The Notification to be displayed. 733 * @param foregroundServiceType must be a subset flags of manifest attribute 734 * {@link android.R.attr#foregroundServiceType} flags. 735 * @throws IllegalArgumentException if param foregroundServiceType is not subset of manifest 736 * attribute {@link android.R.attr#foregroundServiceType}. 737 * @see android.content.pm.ServiceInfo#FOREGROUND_SERVICE_TYPE_MANIFEST 738 */ startForeground(int id, @NonNull Notification notification, @ForegroundServiceType int foregroundServiceType)739 public final void startForeground(int id, @NonNull Notification notification, 740 @ForegroundServiceType int foregroundServiceType) { 741 try { 742 mActivityManager.setServiceForeground( 743 new ComponentName(this, mClassName), mToken, id, 744 notification, 0, foregroundServiceType); 745 } catch (RemoteException ex) { 746 } 747 } 748 749 /** 750 * Synonym for {@link #stopForeground(int)}. 751 * @param removeNotification If true, the {@link #STOP_FOREGROUND_REMOVE} flag 752 * will be supplied. 753 * @see #stopForeground(int) 754 * @see #startForeground(int, Notification) 755 */ stopForeground(boolean removeNotification)756 public final void stopForeground(boolean removeNotification) { 757 stopForeground(removeNotification ? STOP_FOREGROUND_REMOVE : 0); 758 } 759 760 /** 761 * Remove this service from foreground state, allowing it to be killed if 762 * more memory is needed. This does not stop the service from running (for that 763 * you use {@link #stopSelf()} or related methods), just takes it out of the 764 * foreground state. 765 * 766 * @param flags additional behavior options. 767 * @see #startForeground(int, Notification) 768 */ stopForeground(@topForegroundFlags int flags)769 public final void stopForeground(@StopForegroundFlags int flags) { 770 try { 771 mActivityManager.setServiceForeground( 772 new ComponentName(this, mClassName), mToken, 0, null, 773 flags, 0); 774 } catch (RemoteException ex) { 775 } 776 } 777 778 /** 779 * If the service has become a foreground service by calling 780 * {@link #startForeground(int, Notification)} 781 * or {@link #startForeground(int, Notification, int)}, {@link #getForegroundServiceType()} 782 * returns the current foreground service type. 783 * 784 * <p>If there is no foregroundServiceType specified 785 * in manifest, {@link ServiceInfo#FOREGROUND_SERVICE_TYPE_NONE} is returned. </p> 786 * 787 * <p>If the service is not a foreground service, 788 * {@link ServiceInfo#FOREGROUND_SERVICE_TYPE_NONE} is returned.</p> 789 * 790 * @return current foreground service type flags. 791 */ getForegroundServiceType()792 public final @ForegroundServiceType int getForegroundServiceType() { 793 int ret = ServiceInfo.FOREGROUND_SERVICE_TYPE_NONE; 794 try { 795 ret = mActivityManager.getForegroundServiceType( 796 new ComponentName(this, mClassName), mToken); 797 } catch (RemoteException ex) { 798 } 799 return ret; 800 } 801 802 /** 803 * Print the Service's state into the given stream. This gets invoked if 804 * you run "adb shell dumpsys activity service <yourservicename>" 805 * (note that for this command to work, the service must be running, and 806 * you must specify a fully-qualified service name). 807 * This is distinct from "dumpsys <servicename>", which only works for 808 * named system services and which invokes the {@link IBinder#dump} method 809 * on the {@link IBinder} interface registered with ServiceManager. 810 * 811 * @param fd The raw file descriptor that the dump is being sent to. 812 * @param writer The PrintWriter to which you should dump your state. This will be 813 * closed for you after you return. 814 * @param args additional arguments to the dump request. 815 */ dump(FileDescriptor fd, PrintWriter writer, String[] args)816 protected void dump(FileDescriptor fd, PrintWriter writer, String[] args) { 817 writer.println("nothing to dump"); 818 } 819 820 // ------------------ Internal API ------------------ 821 822 /** 823 * @hide 824 */ 825 @UnsupportedAppUsage attach( Context context, ActivityThread thread, String className, IBinder token, Application application, Object activityManager)826 public final void attach( 827 Context context, 828 ActivityThread thread, String className, IBinder token, 829 Application application, Object activityManager) { 830 attachBaseContext(context); 831 mThread = thread; // NOTE: unused - remove? 832 mClassName = className; 833 mToken = token; 834 mApplication = application; 835 mActivityManager = (IActivityManager)activityManager; 836 mStartCompatibility = getApplicationInfo().targetSdkVersion 837 < Build.VERSION_CODES.ECLAIR; 838 } 839 840 /** 841 * @hide 842 * Clean up any references to avoid leaks. 843 */ 844 public final void detachAndCleanUp() { 845 mToken = null; 846 } 847 848 final String getClassName() { 849 return mClassName; 850 } 851 852 // set by the thread after the constructor and before onCreate(Bundle icicle) is called. 853 @UnsupportedAppUsage 854 private ActivityThread mThread = null; 855 @UnsupportedAppUsage 856 private String mClassName = null; 857 @UnsupportedAppUsage 858 private IBinder mToken = null; 859 @UnsupportedAppUsage 860 private Application mApplication = null; 861 @UnsupportedAppUsage 862 private IActivityManager mActivityManager = null; 863 @UnsupportedAppUsage 864 private boolean mStartCompatibility = false; 865 } 866