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