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