public void addListener(AnimatorListener listener){
  if (mListeners == null) {
    mListeners=new ArrayList<AnimatorListener>();
  }
  mListeners.add(listener);
}

public void addListener ( AnimatorListener listener ) { if ( mListeners == null ) { mListeners = new ArrayList < AnimatorListener > ( ) ; } mListeners . add ( listener ) ; }
adds a listener to the set of listeners that are sent events through the life of an animation , such as start , repeat , and end .
