首次运行时MediaPlayer无法工作

Question

我在我的应用程序中添加了MediaPlayer。它工作得很好，但是第一次调用我的表面并初始化MediaPlayer时，纹理变为可见，但是它是白色的，没有视频（但声音正常工作，我的日志显示它工作正常）。

第一次尝试后，它可以完美地工作。但我找不到第一次不起作用的原因。以下是我的代码：

/////////
     mVideoView = (TextureView) mRootView.findViewById(R.id.show_video_content);
        mVideoView.setSurfaceTextureListener(this);
////////
     public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
        Log.i(TAG, "InicializoSurface. Width: " + width + "  HEIGHT:" + height);
        Log.i(TAG, "InicializoSurface. Width: " + mVideoView.getMeasuredWidth() + "  HEIGHT:" + mVideoView.getMeasuredHeight());
        Log.i(TAG, "View transform. Width: " + mVideoView.getWidth() + "  HEIGHT:" + mVideoView.getHeight());


        mMediaSurface = new Surface(mVideoView.getSurfaceTexture());
        initializeMediaPlayer();

    }

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

    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {

        if (mMediaPlayer != null) {
            // Make sure we stop video and release resources when activity is destroyed.
            mMediaPlayer.stop();
            mMediaPlayer.release();
            mMediaPlayer = null;
        }
        return false;
    }
    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surface) {

    }

这是我的自定义MediaPlayer和我在初始化表面时调用的事件：

   private class CustomMediaPlayer extends MediaPlayer implements MediaPlayer.OnCompletionListener, MediaPlayer.OnPreparedListener {

    SurfaceHolder mVideoHolder;

    @Override
    public void onCompletion(MediaPlayer mediaPlayer) {
        if (mediaPlayer != null) {
            mediaPlayer.start();
        }
    }
    @Override
    public void onPrepared(MediaPlayer mediaPlayer) {
        Log.i(TAG,"video preparado");
        mMediaPrepared = true;
    }
}

 private void initializeMediaPlayer(){

    mMediaPlayer = new CustomMediaPlayer();
    Uri uri = Uri.parse(mCameraDataAdapter.getList().get(0).getPath());

    try {
        mMediaPlayer.setDataSource(mActivity, uri);
        mMediaPlayer.setSurface(mMediaSurface);
        mMediaPlayer.prepareAsync();
        mMediaPlayer.setOnPreparedListener(mMediaPlayer);
        mMediaPlayer.setOnCompletionListener(mMediaPlayer);


    } catch (IOException e) {
        e.printStackTrace();
    }


}

最后，在我的onDragListener中调用start()方法：

      case DragEvent.ACTION_DRAG_STARTED:

                if (mCameraDataAdapter.getFirstElement().equalsIgnoreCase("video")) {
                    mThumbnailContainer.setVisibility(View.VISIBLE);
                    mVideoView.setVisibility(View.VISIBLE);


                    Log.i(TAG, "X: " + mVideoView.getX() + "Y: " + mVideoView.getY());


                    if (mVideoView.isAvailable()) {
                        onSurfaceTextureAvailable(mVideoView.getSurfaceTexture(), mVideoView.getWidth(), mVideoView.getHeight());
                    }

                    if (mMediaPlayer == null) {
                        initializeMediaPlayer();
                    }


                    if (mMediaPrepared) {
                        Log.i(TAG,"Comienzo Video");
                        mMediaPlayer.start();
                    }

                } else {
                    mThumbnailContainer.setVisibility(View.VISIBLE);
                    mImageContainer.setVisibility(View.VISIBLE);
                }
                mPreviewThumbIcon.setVisibility(View.INVISIBLE);
                return true;

我已经尝试将prepare()更改为prepareAsync()，或者始终使用“可见”的视图，但我找不到它不能工作的原因。

- Francisco Durdin Garcia

Answer 1

在 Drop & Drag 方法中的 Action_drag_ended 中，每次使用完 MediaPlayer 后都要重置它：

case DragEvent.ACTION_DRAG_STARTED:

selected = null;

if (mCameraDataAdapter.getFirstElement().equalsIgnoreCase("video")) {

    mImageContainer.setVisibility(View.INVISIBLE);
    mVideoView.setVisibility(View.VISIBLE);
    //SurfaceTexture is not called if the Texture is already available, so we call it anyway
    if (mVideoView.isAvailable()) {
        onSurfaceTextureAvailable(mVideoView.getSurfaceTexture(), mVideoView.getMeasuredWidth(), mVideoView.getMeasuredHeight());
    }

} else {
    mVideoView.setVisibility(View.INVISIBLE);
    mImageContainer.setVisibility(View.VISIBLE);
}
mPreviewThumbIcon.setVisibility(View.INVISIBLE);
return true;

另外，将Mediaplayer.start放置在自定义的PreparedListener中。

private class CustomMediaPlayer extends MediaPlayer implements MediaPlayer.OnCompletionListener, MediaPlayer.OnPreparedListener {

@Override
public void onCompletion(MediaPlayer mediaPlayer) {
    if (mediaPlayer != null) {
        mediaPlayer.start();
    }
}
//We start the video when its available
@Override
public void onPrepared(MediaPlayer mediaPlayer) {
    Log.i(TAG,"Video Prepare");
    mediaPlayer.start();
}
}

希望这能对你有所帮助。祝你好运！

- user2683616