无法观看ExoPlayer视频，但我听到声音了

Question

我在Coverflow视图中设置了 Exoplayer ，该播放器工作正常。

原因：但是在我尝试通过各种方法解决它的屏幕上， Exoplayerview不可见。

到目前为止，我已经完成了一些代码，发布在下面，

 private void playMedia(String video) {
        mBandwidthMeter = new DefaultBandwidthMeter();
        mAdaptiveTrackSelectionFactory = new AdaptiveTrackSelection.Factory(mBandwidthMeter);
        mTrackSelector = new DefaultTrackSelector(mAdaptiveTrackSelectionFactory);
        mLoadControl = new DefaultLoadControl();
        mSimpleExoPlayer = ExoPlayerFactory.newSimpleInstance(getApplicationContext(), mTrackSelector, mLoadControl);

        videoPlayback.setPlayer(mSimpleExoPlayer);

        DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();

        // Produces DataSource instances through which media data is loaded.
        DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(getApplicationContext(),
                Util.getUserAgent(getApplicationContext(), "com.exoplayerdemo"), bandwidthMeter);

        // Produces Extractor instances for parsing the media data.
        ExtractorsFactory extractorsFactory = new DefaultExtractorsFactory();

        // This is the MediaSource representing the media to be played.
        MediaSource videoSource = new ExtractorMediaSource(Uri.parse(video),
                dataSourceFactory, extractorsFactory, null, null);

        // Prepare the player with the source.
        mLoopingMediaSource = new LoopingMediaSource(videoSource);
        mSimpleExoPlayer.prepare(videoSource);
        mSimpleExoPlayer.setPlayWhenReady(true);
        mSimpleExoPlayer.addListener(new ExoPlayer.EventListener() {

            @Override
            public void onTimelineChanged(Timeline timeline, Object manifest, int reason) {}

            @Override
            public void onTracksChanged(TrackGroupArray trackGroups, TrackSelectionArray trackSelections) {}

            @Override
            public void onLoadingChanged(boolean isLoading) {}

            @Override
            public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {}

            @Override
            public void onRepeatModeChanged(int repeatMode) {}

            @Override
            public void onShuffleModeEnabledChanged(boolean shuffleModeEnabled) {}

            @Override
            public void onPlayerError(ExoPlaybackException error) {
                //Toast.makeText(EducationDetailView.this, error.getMessage(), Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onPositionDiscontinuity(int reason) {}

            @Override
            public void onPlaybackParametersChanged(PlaybackParameters playbackParameters) {}

            @Override
            public void onSeekProcessed() {}
        });
    }

从下面的代码中，你们可以帮助我解决这个问题，并能够找出问题所在。