1

在我的应用程序中，我有一个将 BroadcastReceiver 注册到onStart()方法中的服务：

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);
        }
    }
}

它工作正常。但我会在其中注销此 BroadcastReceiverelse并收到此错误：

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 com.myservice.Service@460ce7d8 with Intent { cmp=com.myservice/.Service (has extras) }: java.lang.IllegalArgumentException: Receiver not registered: com.myreceiver.ScreenReceiver@46079370
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$MethodAndArgsCaller.run(ZygoteInit.java:868)
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):     at dalvik.system.NativeStart.main(Native Method)
01-25 09:30:03.730: ERROR/AndroidRuntime(11748): Caused by: java.lang.IllegalArgumentException: Receiver not registered: com.myreceiver.ScreenReceiver@46079370
01-25 09:30:03.730: ERROR/AndroidRuntime(11748):     at android.app.ActivityThread$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

你能帮助我吗？

4

1 回答 1

4

修改你的代码如下

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;
        }
    }
}

调用 unregisterReceiver() 不会将 screenReceiver 设置为 null，并且当控件到达该块时，可能并不总是您的接收器已注册。例如，考虑按顺序进行，

  1. if(something...)为真，所以 screenReceiver 被实例化并注册。
  2. if(something...)这次是假的，所以 screenReceiver 是未注册的。
  3. if(something...)再次为假，在这里，screenReceiver 在步骤 1 中被实例化，因此它不为空，但在步骤 2 中未注册，因此出现异常“接收器未注册：com.myreceiver.ScreenReceiver@46079370”。

设置screenReceiver为null后，依次考虑以上3个步骤。它将正确执行。

于 2011-01-25T09:11:46.797 回答