public void addArcSeriesItemListener(@NonNull SeriesItemListener listener){
  if (mListeners == null) {
    mListeners=new ArrayList<>();
  }
  mListeners.add(listener);
}

public void addArcSeriesItemListener ( @ NonNull SeriesItemListener listener ) { if ( mListeners == null ) { mListeners = new ArrayList < > ( ) ; } mListeners . add ( listener ) ; }
set a listener to get notification of completion of animation
