註銷廣播接收器

在我的應用我已經是註冊一個BroadcastReceiver爲onStart()方法的服務：註銷廣播接收器

public void onStart() { 
    if(something....) { 
     IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON); 
     filter.addAction(Intent.ACTION_SCREEN_OFF); 
     screenReceiver = new ScreenReceiver(); 
     registerReceiver(screenReceiver, filter); 
    } else { 
     if(screenReceiver != null) { 
      unregisterReceiver(screenReceiver); 
     } 
    } 
}

和它工作正常。不過，我想註銷內else這個廣播接收器，我收到此錯誤：

01-25 09:30:03.730: ERROR/AndroidRuntime(11748): FATAL EXCEPTION: main 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748): java.lang.RuntimeException: Unable to start service [email protected] with Intent { cmp=com.myservice/.Service (has extras) }: java.lang.IllegalArgumentException: Receiver not registered: [email protected] 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3063) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.app.ActivityThread.access$3600(ActivityThread.java:125) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2096) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.os.Handler.dispatchMessage(Handler.java:99) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.os.Looper.loop(Looper.java:123) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.app.ActivityThread.main(ActivityThread.java:4627) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at java.lang.reflect.Method.invokeNative(Native Method) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at java.lang.reflect.Method.invoke(Method.java:521) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at dalvik.system.NativeStart.main(Native Method) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748): Caused by: java.lang.IllegalArgumentException: Receiver not registered: [email protected] 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.app.ActivityThread$PackageInfo.forgetReceiverDispatcher(ActivityThread.java:793) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.app.ContextImpl.unregisterReceiver(ContextImpl.java:814) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.content.ContextWrapper.unregisterReceiver(ContextWrapper.java:331) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at com.myservice.Service.onStart(Service.java:291) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.app.Service.onStartCommand(Service.java:420) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:3053) 
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):  ... 10 more

你能幫助我嗎？

來源

2011-01-25 CeccoCQ

修改你的代碼如下

public void onStart() { 
    if(something....) { 
     IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_ON); 
     filter.addAction(Intent.ACTION_SCREEN_OFF); 
     screenReceiver = new ScreenReceiver(); 
     registerReceiver(screenReceiver, filter); 
    } else { 
     if(screenReceiver != null) { 
      unregisterReceiver(screenReceiver); 
      screenReceiver = null; 
     } 
    } 
}

調用unregisterReceiver（）不設置screenReceiver爲null，當控制達到該塊，也未必永遠是你的接收器被註冊的情況。例如按順序考慮以下內容：

if(something...)爲真，因此screenReceiver被實例化並註冊。
if(something...)這次是錯誤的，所以screenReceiver是未註冊的。
if(something...)又是錯誤的，在這裏，screenReceiver在步驟1中被實例化，因此它不是null，但它在步驟2中未註冊，因此該例外「Receiver not registered：[email protected]」。

將screenReceiver設置爲空後，請考慮按順序在3個以上的步驟。它會正確執行。

來源

2011-01-25 09:11:46

你有權利。謝謝！！ – CeccoCQ 2011-01-25 09:40:15

註銷廣播接收器

回答

相關問題