Android Exoplayer 2-如何显示没有uri但带有字符串的字幕？

我想用exoplayer 2显示预加载的字幕，并向播放器提供一个基于webvtt的字符串，以便它处理字幕

我的系统应该这样工作：

我向我的服务器发送请求以加密字幕 我解密服务器响应以获得字幕字符串webvtt格式 我想把这根线给我的播放器。Exoplayer应该能够像使用webvtt uri一样显示SUB。 我不想使用系统文件，因为它会让用户可以访问字幕文件

请参见以下我的活动代码：

//Class Player Activity

// ... activity code ...

public void initializePlayer(){
 //... code intialization of player ...
 mVideoEventListener = new VideoEventListener(this);

 if(mEpisode.getVideo().getSubtitle() == null) {
  mEpisode.getVideo().loadSubtitle(this, Video.VO, mVideoEventListener);
        return;
 }
 hasSubtitle = true;
 startPlayer();
}

public void startPlayer(){
 boolean haveStartPosition = startWindow != C.INDEX_UNSET;
 if (haveStartPosition) {
  mPlayer.seekTo(startWindow, startPosition);
 }
 if(hasVideo && hasSubtitle){
  MergingMediaSource mergedSource = new MergingMediaSource(mVideoSource, mSubtitleSource);
  mPlayer.prepare(mergedSource, !haveStartPosition, false);
 }
}

// ... activity code ...

private class VideoEventListener implements
 Video.SubtitleListener,
 LoadBalancer.OnLoadBalanceListener{

 private final Context mCtx;

 VideoEventListener(Context ctx) {
  mCtx = ctx;
 }

 @Override
 public void onSubtitleLoaded(String subtitle) {
  hasSubtitle = true;

  Format subtitleFormat = Format.createTextSampleFormat(null, MimeTypes.TEXT_VTT, C.SELECTION_FLAG_FORCED, "fr");

  mSubtitleSource = //My problem : How create a mediaSource with variable "subtitle" in format WebVTT ?

  startPlayer();
 }
}

---

我在代码下面找到了我的答案：

    @Override
    public void onSubtitleLoaded(String s) {
        hasSubtitle = true;

        Format subtitleFormat = Format.createTextSampleFormat(
                "test", MimeTypes.TEXT_VTT, C.SELECTION_FLAG_FORCED, "fr");

        mSubtitleSource =
                new SingleSampleMediaSource.Factory(new CustomDataSourceFactory(ctx, null, s.getBytes()))
                        .createMediaSource(Uri.parse(""), subtitleFormat, C.TIME_UNSET);

    }

CustomDataSourceFactory类

public class CustomDataSourceFactory implements DataSource.Factory {
    private final Context context;
    private final @Nullable TransferListener listener;
    private byte[] subtitles;

    public CustomDataSourceFactory(
        Context context,
        @Nullable TransferListener listener,
        byte[] subtitles) {
        this.context = context.getApplicationContext();
        this.subtitles = subtitles;
        this.listener = listener;
    }

    @Override
    public DataSource createDataSource() {
        ByteArrayDataSource dataSource = new ByteArrayDataSource(subtitles);
        if (listener != null) {
            dataSource.addTransferListener(listener);
        }
        return dataSource;
    }
}