code: public void play() {
          checkState();
          if (mState == STATE_PAUSED) {
              PlaybackService.resume(getContext(), mClientKey);
          } else if (mState == STATE_STOPPED) {
              SoundCloudTrack track = mPlayerPlaylist.getCurrentTrack();
              if (track != null) {
                  PlaybackService.play(getContext(), mClientKey, track);
              } else {
                  return;
              }
          }
          mState = STATE_PLAYING;
      }
docs: Start the playback. First track of the queue will be played.
  <p/>
  If the SoundCloud player is currently paused, the current track will be restart at the stopped position.