在Android中取消注册BroadcastReceiver

Question

我正在使用服务，实际上我想要的是每分钟调用一次事件，假设我想每分钟打印一次日志，什么代码我可以正常工作，但是只有当活动处于前台时，当我最小化应用程序时或关闭它，它会给出如下错误：

08-19 17:31:33.936: E/AndroidRuntime(14264): FATAL EXCEPTION: main
08-19 17:31:33.936: E/AndroidRuntime(14264): java.lang.RuntimeException: Unable to stop activity    {com.example/com.example.MainActivity}: java.lang.IllegalArgumentException: Receiver not registered:   com.example.MainActivity$1@41117730
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3629)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.ActivityThread.handleStopActivity(ActivityThread.java:3675)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.ActivityThread.access$900(ActivityThread.java:162)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1393)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.os.Handler.dispatchMessage(Handler.java:99)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.os.Looper.loop(Looper.java:158)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.ActivityThread.main(ActivityThread.java:5751)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at java.lang.reflect.Method.invokeNative(Native Method)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at java.lang.reflect.Method.invoke(Method.java:511)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1083)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:850)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at dalvik.system.NativeStart.main(Native Method)
08-19 17:31:33.936: E/AndroidRuntime(14264): Caused by: java.lang.IllegalArgumentException: Receiver not registered: com.example.MainActivity$1@41117730
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.LoadedApk.forgetReceiverDispatcher(LoadedApk.java:719)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.ContextImpl.unregisterReceiver(ContextImpl.java:1620)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.content.ContextWrapper.unregisterReceiver(ContextWrapper.java:445)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at com.example.MainActivity.onStop(MainActivity.java:143)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.Instrumentation.callActivityOnStop(Instrumentation.java:1305)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.Activity.performStop(Activity.java:5338)
08-19 17:31:33.936: E/AndroidRuntime(14264):    at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3626)
08-19 17:31:33.936: E/AndroidRuntime(14264):    ... 11 more

我的活动代码如下：

public class MainActivity extends Activity 
{


BroadcastReceiver mBroadcastTime;

@Override
public void onCreate(Bundle savedInstanceState) 
{

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);


mBroadcastTime = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        Intent service1 = new Intent(context, MyAlarmService.class);
        context.startService(service1);
    }

};

IntentFilter mTime = new IntentFilter(Intent.ACTION_TIME_TICK);
registerReceiver(mBroadcastTime, mTime);


}

@Override
public void onPause()
{
  super.onPause();
  if(mBroadcastTime != null){
      unregisterReceiver(mBroadcastTime);
      Log.v("BROADCAST ON PAUSE", "UNREGISTERED");
  }
}

@Override
public void onStop()
{
  super.onStop();
  if(mBroadcastTime != null){
      unregisterReceiver(mBroadcastTime);
      Log.v("BROADCAST ON STOP", "UNREGISTERED");
  }
}

@Override
public void onDestroy()
{
  super.onDestroy();
  if(mBroadcastTime != null){
      unregisterReceiver(mBroadcastTime);
      Log.v("BROADCAST ON DESTROY", "UNREGISTERED");
  }
}

}

Answer 1

问题是您要尝试注销一次以上的广播接收器。 您应该检查两件事：对象是否为null是否已注册

请关注此问题或从onStop()和onDestroy()删除注销方法

还请记住，如果您在onPause上取消注册广播，则应在onResume()再次进行注册。

IMO最简单的方法是：

• 从onStrop()和onDestroy()取消注销
• 将广播的寄存器从onCreate()移到onResume()

请研究一下Android中的活动生命周期-应该了解每个Android开发人员；）- 这里您需要的一切

Answer 2

您可以在onCreate中注册接收者，而在onPause中取消注册。 问题在于，在onCreate中仅注册一次。 因此，如果onPause至少被调用一次，那么您将无法注销两次。 所以最好的办法是在onResume中注册您的接收器