我有这段用于显示 MediaController 的代码，但是当我调用 Show() 方法时它给了我一个 fatal error 。

MediaPlayer 本身处理 Service 并从 MediaPlayerControl 接口(interface)获取 Intent。

我的代码:

    @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

            mediaController =  new MediaController(this, false);
            mediaController.setMediaPlayer(mediaPlayerControl);
            mediaController.setAnchorView(findViewById(R.id.mediaController));
            mediaController.setEnabled(true);
            mediaController.show(0);
    }

    //implements MediaPlayerControl interface
    private MediaPlayerControl mediaPlayerControl = new MediaPlayerControl()
    {

            //Override the methods to send Intent to the MediaPlayer Service
            ....
            ....
     };

我的日志:

07-27 11:03:07.365: E/AndroidRuntime(328): FATAL EXCEPTION: main 07-27 11:03:07.365: E/AndroidRuntime(328): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.radius100fm/com.example.radius100fm.MainActivity}: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running? 07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.os.Handler.dispatchMessage(Handler.java:99) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.os.Looper.loop(Looper.java:123) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.main(ActivityThread.java:3683) 07-27 11:03:07.365: E/AndroidRuntime(328): at java.lang.reflect.Method.invokeNative(Native Method) 07-27 11:03:07.365: E/AndroidRuntime(328): at java.lang.reflect.Method.invoke(Method.java:507) 07-27 11:03:07.365: E/AndroidRuntime(328): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 07-27 11:03:07.365: E/AndroidRuntime(328): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 07-27 11:03:07.365: E/AndroidRuntime(328): at dalvik.system.NativeStart.main(Native Method) 07-27 11:03:07.365: E/AndroidRuntime(328): Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running? 07-27 11:03:07.365: E/AndroidRuntime(328): at android.view.ViewRoot.setView(ViewRoot.java:527) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.view.Window$LocalWindowManager.addView(Window.java:424) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.widget.MediaController.show(MediaController.java:304) 07-27 11:03:07.365: E/AndroidRuntime(328): at com.example.radius100fm.MainActivity.onCreate(MainActivity.java:100) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 07-27 11:03:07.365: E/AndroidRuntime(328): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 07-27 11:03:07.365: E/AndroidRuntime(328): ... 11 more

我的代码有什么问题？

最佳答案

使用这个方法。

@Override
public void onWindowFocusChanged(boolean hasFocus) {
   super.onWindowFocusChanged(hasFocus);
   if(mediaController != null)
      mediaController.show(0);
}

关于java - MediaController - 调用 Show() 时出错，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17897162/