MediaController - Error when Show() called

Question

I have this code for show the MediaController, but it give me a fatal error when I'm calling to Show() method.

The MediaPlayer itself working on Service and get Intent from the MediaPlayerControl interface.

My code:

    @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
            ....
            ....
     };

my logcat:

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

What is the problem with my code?

Answer 1

Use this method.

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

Answer 2

I got the same problem and after several hours got the solution. I did the following:

Summary:

The Activity class implements the interfaces: MediaPlayer.OnPreparedListener and MediaController.MediaPlayerControl

• OnCreate. setContentView.

• onStart. Create MediaPlayer and MediaController, start the listener with setOnPreparedListener and call prepare() method of MediaPlayer.

• Implement method onPrepared. Link the mediaController with the mediaPlayer, start mediaPlayer and here is where the method show() is called using a handler, only when we know that mediaPlayer is ready.

My code:

public class MainActivity extends Activity implements MediaPlayer.OnPreparedListener, MediaController.MediaPlayerControl {

private static final String TAG = "AudioPlayer";

private MediaPlayer mediaPlayer;

private MediaController mediaController;

private Handler handler = new Handler();


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);


}

@Override
protected void onStart() {
    Log.d(TAG, "Play - onStart");
    super.onStart();

    mediaPlayer = new MediaPlayer();
    mediaController = new MediaController(this);

    mediaPlayer.setOnPreparedListener(this);

    try {
        AssetFileDescriptor afd = getApplicationContext().getResources().openRawResourceFd(R.raw.audio_example);
        mediaPlayer.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getDeclaredLength());

        mediaPlayer.prepare();
        afd.close();
    } catch (IOException e) {
        Log.e(TAG, "Error opening audio: " + e.getCause());
    }

}

// override this method because of the OnPreparedListener interface

@Override
public void onPrepared(MediaPlayer mediaPlayer) {
    Log.d(TAG, "Play - onPrepared");
    mediaController.setMediaPlayer(this);
    mediaController.setAnchorView(findViewById(R.id.mediaController1));
    mediaPlayer.start();

    handler.post(new Runnable() {

        @Override
        public void run() {
            mediaController.setEnabled(true);
            mediaController.show(0);

        }
    });

}

    // override these methods because of the MediaController.MediaPlayerControl interface

@Override
public boolean canPause() {
    return true;
}

@Override
public boolean canSeekBackward() {
    return true;
}

@Override
public boolean canSeekForward() {
    return true;
}

@Override
public int getAudioSessionId() {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public int getBufferPercentage() {
    // TODO Auto-generated method stub
    return 0;
}

@Override
public int getCurrentPosition() {
    return mediaPlayer.getCurrentPosition();
}

@Override
public int getDuration() {
    return mediaPlayer.getDuration();
}

@Override
public boolean isPlaying() {
    return mediaPlayer.isPlaying();
}

@Override
public void pause() {
    mediaPlayer.pause();
}

@Override
public void seekTo(int pos) {
    mediaPlayer.seekTo(pos);
}

@Override
public void start() {
    mediaPlayer.start();
}

    // release resources before kill the Activity

@Override
protected void onStop() {
    Log.d(TAG, "Play - onStop");
    super.onStop();
    if (mediaPlayer != null) {
        mediaController.hide();
        mediaPlayer.stop();
        mediaPlayer.release();
        mediaPlayer = null;
    }
} }