Fixed RTL languages punctuation mark issue

[orenskl]

Changes
Add the unicode LTRM character for subtitles

Issues
Fixed #4296

[nielsvanvelzen]

While I'm sure this fixes the LTR issues, I'm not sure if this is a proper fix for the underlying issue. Modifying each line to force unicode directional marks into them seems like a hack we should not need to do, and it may even introduce side-effects.

[orenskl]

I agree this is a hack/patch for this issue, while I did tested this with both LTR and RTL subtitles and it seems ok.
Subtitle direction should be handled correctly in the SubtitleView but I think there is a bug or an issue in the media3 library so I guess we will have to wait for it to be fixed.

[itsrn]

I tried your method, however it only fixed the RTL of the first subtitle line. Moreover, it sometimes mixed together English letters or numbers inside RTL subtitle lines. For this reason, I decided to modify your code, which works only with Hebrew, but is easily adaptable to other RTL languages.:

@Override
public void onCues(@NonNull CueGroup cueGroup) {
  List < Cue > modifiedCues = new ArrayList < > ();
  final String LTRM = "\u200E"; // Left-to-Right Mark

  for (Cue cue: cueGroup.cues) {
    CharSequence originalText = cue.text;

    if (originalText == null) {
      modifiedCues.add(cue);
      continue;
    }

    boolean containsHebrew = false;
    String textStr = originalText.toString();
    for (int i = 0; i < textStr.length(); i++) {
      char c = textStr.charAt(i);
      if ((c >= 0x0590 && c <= 0x05FF) || // Hebrew range
        (c >= 0xFB1D && c <= 0xFB4F)) { // Hebrew presentation forms
        containsHebrew = true;
        break;
      }
    }

    CharSequence modifiedText;
    if (containsHebrew) {
      String[] lines = textStr.split("\n");
      StringBuilder ltrText = new StringBuilder();

      for (int i = 0; i < lines.length; i++) {
        if (i > 0) ltrText.append("\n");
        ltrText.append(LTRM).append(lines[i]);
      }

      modifiedText = ltrText.toString();
    } else {
      modifiedText = originalText;
    }

    Cue.Builder builder = new Cue.Builder()
      .setText(modifiedText)
      .setPosition(cue.position)
      .setLine(cue.line, cue.lineType);

    if (cue.size != Cue.DIMEN_UNSET) {
      builder.setSize(cue.size);
    }
    if (cue.textAlignment != null) {
      builder.setTextAlignment(cue.textAlignment);
    }

    modifiedCues.add(builder.build());
  }

  CueGroup cg = new CueGroup(modifiedCues, cueGroup.presentationTimeUs);
  mExoPlayerView.getSubtitleView().setCues(cg.cues);
}

This is ideal for someone looking for a temporary solution (although it may cause additional complications, as previously indicated, even though I couldn't find any with Hebrew and English subtitles).