code: public void play(int position) {
          checkState();
          ArrayList<SoundCloudTrack> tracks = mPlayerPlaylist.getPlaylist().getTracks();
          if (position >= 0 && position < tracks.size()) {
              SoundCloudTrack trackToPlay = tracks.get(position);
              mPlayerPlaylist.setPlayingTrack(position);
              PlaybackService.play(getContext(), mClientKey, trackToPlay);
          }
  
      }
docs: Play a track at a given position in the player playlist.
  
  @param position position of the track in the playlist.