android - 泄露 Intent 和警报管理器

Question

我正在尝试创建身份验证系统，如果设备关闭 (SCREEN_OFF) 超过 INTERVAL，该系统会弹出登录窗口。

我已经注册了一个 BroadcastReceiver 来监听可启动 Activity 的 onCreate() 中的 SCREEN_ON/OFF 事件:

/* Listen to Screen On & Off events */
  IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON);
  filter.addAction(Intent.ACTION_SCREEN_OFF);
  BroadcastReceiver screenOnOff = new ScreenOnOff();
  registerReceiver(screenOnOff, filter);

ScreenOnOff -- 是一个 BroadcastReceiver，除其他外，它还可以:

@Override
 public void onReceive(Context context, Intent intent) {


mAuthenticationIntent = PendingIntent.getActivity(context, 0,
    new Intent(context, AuthenticationActivity.class), 0);

String action = intent.getAction();

if (action.equals(Intent.ACTION_SCREEN_OFF)) {
   AlarmManager mAlarmManager = (AlarmManager) context
     .getSystemService(context.ALARM_SERVICE);
   mAlarmManager.set(AlarmManager.ELAPSED_REALTIME, System
     .currentTimeMillis()
     + interval, mAuthenticationIntent);

   Log.d(LOG_TAG, "Alarm Set!");
  }

当警报响起时，程序崩溃:

08-27 19:18:02.207: ERROR/ActivityThread(3165): Activity com.artoo.ArtooSlateActivity has leaked IntentReceiver com.artoo.authentication.ScreenOnOff@4495bca0 that was originally registered here. Are you missing a call to unregisterReceiver()?
08-27 19:18:02.207: ERROR/ActivityThread(3165): android.app.IntentReceiverLeaked: Activity com.artoo.ArtooSlateActivity has leaked IntentReceiver com.artoo.authentication.ScreenOnOff@4495bca0 that was originally registered here. Are you missing a call to unregisterReceiver()?
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ActivityThread$PackageInfo$ReceiverDispatcher.<init>(ActivityThread.java:939)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ActivityThread$PackageInfo.getReceiverDispatcher(ActivityThread.java:734)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ContextImpl.registerReceiverInternal(ContextImpl.java:791)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ContextImpl.registerReceiver(ContextImpl.java:778)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ContextImpl.registerReceiver(ContextImpl.java:772)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:318)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at com.artoo.ArtooSlateActivity.onCreate(ArtooSlateActivity.java:50)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3815)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ActivityThread.access$2400(ActivityThread.java:125)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2037)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.os.Looper.loop(Looper.java:123)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at android.app.ActivityThread.main(ActivityThread.java:4627)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at java.lang.reflect.Method.invokeNative(Native Method)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at java.lang.reflect.Method.invoke(Method.java:521)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
08-27 19:18:02.207: ERROR/ActivityThread(3165):     at dalvik.system.NativeStart.main(Native Method)

任何帮助将不胜感激。

谢谢，萨米尔

Answer 1

由于您动态注册接收器，系统知道您正在泄漏内存，因为您从未对其调用 unregister。显然您不想取消注册，因为您需要监听 SCREEN_ON/OFF 事件。

解决方案是在您的 Manifest.xml 中注册接收器

Base class for code that will receive intents sent by sendBroadcast(). You can either dynamically register an instance of this class with Context.registerReceiver() or statically publish an implementation through the tag in your AndroidManifest.xml. Note: If registering a receiver in your Activity.onResume() implementation, you should unregister it in Activity.onPause(). (You won't receive intents when paused, and this will cut down on unnecessary system overhead). Do not unregister in Activity.onSaveInstanceState(), because this won't be called if the user moves back in the history stack