NullPointerException与Android MediaPlayer

Question

In my Android app, I have a mediaPlayer that plays a video from a URL. I have a button that the user selects when they want to close out the video and return to the previous activity. When the user clicks on the button currently, the app crashes with the following error log:

android.view.WindowLeaked: Activity com.bip.activities.MediaPreview has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{42a50290 V.E..... R.....ID 0,0-800,117} that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:348)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:248)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
at android.widget.MediaController.show(MediaController.java:346)
at android.widget.MediaController.show(MediaController.java:306)
at com.bip.activities.MediaPreview$playUploadedVideo.onPostExecute(MediaPreview.java:834)
at com.bip.activities.MediaPreview$playUploadedVideo.onPostExecute(MediaPreview.java:1)

Shutting down VM
FATAL EXCEPTION: main
Process: com.bip.activities, PID: 26651
java.lang.NullPointerException at com.bip.activities.MediaPreview$playUploadedVideo.getCurrentPosition(MediaPreview.java:868)
at android.widget.MediaController.setProgress(MediaController.java:423)
at android.widget.MediaController.access$500(MediaController.java:71)
at android.widget.MediaController$3.handleMessage(MediaController.java:394)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)

Here is how I load the player:

 public class playUploadedVideo extends AsyncTask<String, Void, Boolean>
            implements OnBufferingUpdateListener, OnCompletionListener,
            OnPreparedListener, OnVideoSizeChangedListener, MediaPlayerControl {

    private ImageButton okay;
    private MediaPlayer s3VideoPlayer;

    ...

    s3VideoPlayer = MediaPlayer.create(this.context,
                        Uri.parse(arg0[0]));
                s3VideoPlayer.setSurface(s);
                s3VideoPlayer.setOnBufferingUpdateListener(this);
                s3VideoPlayer.setOnCompletionListener(this);
                s3VideoPlayer.setOnPreparedListener(this);
                s3VideoPlayer.setScreenOnWhilePlaying(true);
                s3VideoPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);

       okay.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // stop mediaplayer if running
            if(s3VideoPlayer != null){
                try{
                    Log.d(TAG, "Stopping media player from okay button");
                    if(s3VideoPlayer.isPlaying()){
                        s3VideoPlayer.stop();    
                    }
                    s3VideoPlayer.release();
                    s3VideoPlayer = null;
                }catch(Exception ex){
                    ex.printStackTrace();
                }
            }
            StepDisplay.setAlreadyLoaded(true);
            Intent returnIntent = getIntent();
            setResult(RESULT_CANCELED, returnIntent);
            finish();
        }
    });

@Override
public void onStop() {
    super.onStop();
        if (s3VideoPlayer!=null){
            try{
                s3VideoPlayer.stop();
            }catch(Exception ex){
                ex.printStackTrace();
            }
    }
}

I don't explicitly call getCurrentPosition in my code. Is there way to ensure it doesn't get called then the video is released?

How do I get rid of the nullPointerException / WindowLeak to successfully close out the video before returning to the previous activity?

Answer 1

当我关闭视频时，好像隐藏了mediacontroller消除了问题。