android MediaPlayer黑屏onResume

Question

我正在开发一款在可扩展屏幕上播放视频的Android应用。 对于容器，我使用的是包含TextureView的片段。

在TextureView中，我使用MediaPlayer对象播放视频。我已经重写了UserVideoFragment类的onPause（）和onResume（）方法来暂停/恢复视频。

逻辑是，如果缩小视频，那么即使返回到屏幕，视频也应暂停。 如果视频是全屏的，那么视频应该播放。

我面临的问题是当用户回家时，然后返回到按比例缩小模式片段的活动 mediaplayer TextureView显示黑屏。

这是代码

MainActivity.java

private boolean recordingVideo;
private float scaleFactor;
private int marginPixels;
private long animDuration;

private Button btnRecord;
private FragmentManager fragmentManager;
private UserVideoFragment fragmentUserVideo;
private ExpertRecordingFragment fragmentExpertRecording;

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

    UIUtils.hideActionAndStatusBar(getSupportActionBar(), getWindow());

    init();

    btnRecord = (Button) findViewById(R.id.btnRecord);
    fragmentManager = getFragmentManager();

    btnRecord.setOnClickListener(new RecordButtonListener());
}

private void init(){
    recordingVideo = false;
    scaleFactor = 0.2f;
    marginPixels = 32;
    animDuration = 250;
}


private class RecordButtonListener implements View.OnClickListener{

    @Override
    public void onClick(View view) {
        fragmentUserVideo = (UserVideoFragment) fragmentManager.findFragmentById(R.id.fragmentUserVideo);
        fragmentExpertRecording = (ExpertRecordingFragment) fragmentManager.findFragmentById(R.id.fragmentExpertRecording);

        View userVideoView = fragmentUserVideo.getView();
        if(!recordingVideo){
            animateView(userVideoView, 0f, userVideoView.getHeight(), scaleFactor, marginPixels, marginPixels, animDuration);
        }

        if(recordingVideo){
            animateView(userVideoView, 0f, userVideoView.getHeight(), 1f, 0, 0, animDuration);
        }

        recordingVideo = !recordingVideo;
        fragmentUserVideo.onExpertVideoRecordingStarted(recordingVideo);
        fragmentExpertRecording.onExpertVideoRecordingStarted(recordingVideo);
    }
}

private void animateView(View view, float pivotX, float pivotY,
                         float scalingFactor, int marginPixelsX, int marginPixelsY, long duration){
    view.setPivotX(pivotX);
    view.setPivotY(pivotY);
    view.animate()
            .scaleX(scalingFactor)
            .scaleY(scalingFactor)
            .x(marginPixelsX)
            .y(-marginPixelsY)
            .setDuration(duration);
}

public interface OnExpertVideoRecordingStartedListener{
    public void onExpertVideoRecordingStarted(boolean recording);
}

UserVideoFragment.java

    private MediaPlayer mediaPlayer;
private TextureView userVideoTextureView;
private boolean mediaSourceSet;
private int mediaPausePosition;
private boolean recording;



@Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment

    View view = inflater.inflate(R.layout.fragment_user_video, container, false);;

    mediaPlayer = new MediaPlayer();
    mediaPlayer.setOnCompletionListener(new MediaPlayerOnCompletionListener());
    mediaSourceSet = false;
    mediaPausePosition = 0;
    recording = false;
    userVideoTextureView = (TextureView) view.findViewById(R.id.userVideoTextureView);
    userVideoTextureView.setSurfaceTextureListener(new UserVideoTextureViewListener());


    return view;
}



@Override
public void onPause(){
    super.onPause();
    if(mediaPlayer != null && mediaPlayer.isPlaying()){
        mediaPlayer.pause();
    }
}

@Override
public void onResume(){
    super.onResume();
    if(mediaPlayer != null){
        if(recording) {
            mediaPlayer.seekTo(mediaPausePosition);
            userVideoTextureView.requestLayout();
        }

        if(!recording){
            mediaPlayer.start();
        }
    }
}


@Override
public void onDestroy(){
    if(mediaPlayer != null){
        mediaPlayer.stop();
        mediaPlayer.release();
        mediaPlayer = null;
    }
    super.onDestroy();
}

private class UserVideoTextureViewListener implements TextureView.SurfaceTextureListener{

    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int width, int height) {
        Surface mediaSurface = new Surface(surfaceTexture);
        try{
            if(!mediaSourceSet){
                //mediaPlayer.setDataSource("http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4");
                mediaPlayer.setDataSource("http://videocdn.bodybuilding.com/video/mp4/62000/62792m.mp4");
                mediaPlayer.setSurface(mediaSurface);
                mediaPlayer.prepare();
                UIUtils.adjustAspectRatio(userVideoTextureView, mediaPlayer.getVideoWidth(), mediaPlayer.getVideoHeight());
                mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
                    @Override
                    public void onPrepared(MediaPlayer mediaPlayer) {
                        mediaPlayer.start();
                    }
                });
                mediaSourceSet = true;
            }

            if(mediaSourceSet){
                mediaPlayer.setSurface(mediaSurface);
                mediaPlayer.prepareAsync();
                UIUtils.adjustAspectRatio(userVideoTextureView, mediaPlayer.getVideoWidth(), mediaPlayer.getVideoHeight());
            }
        }
        catch(IOException e){
            e.printStackTrace();
        }
        catch(IllegalStateException e){
            e.printStackTrace();
        }
    }

    @Override
    public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int width, int height) {

    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
        return false;
    }

    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {

    }
}

private class MediaPlayerOnCompletionListener implements MediaPlayer.OnCompletionListener{

    @Override
    public void onCompletion(MediaPlayer mediaPlayer) {
    }
}



public void onExpertVideoRecordingStarted(boolean recording){
        if(recording){
            if(mediaPlayer != null && mediaPlayer.isPlaying()){
                mediaPlayer.pause();
                mediaPausePosition = mediaPlayer.getCurrentPosition();
            }
        }

        if(!recording){
            if(mediaPlayer != null && !mediaPlayer.isPlaying()){
                mediaPlayer.start();
            }
        }

        this.recording = recording;
    }