code: private void setPlaying(boolean playing) {
          PlaybackState oldState = currentSimpleState();
          if (oldState != null && oldState.playing != playing) {
              setPlaybackState(oldState.player, oldState.position, playing);
          }
      }
docs: Set whether the player holding the waveform is playing, which changes the indicator color to white from red.
  This method can only be used in situations where the component is tied to a single player, and therefore has
  a single playback position.
  
  @param playing if {@code true}, draw the position marker in white, otherwise red
  
  @see #setPlaybackState