public void addButtonPressedListener(FieldConfigStringButtonInterface listener){
  if (buttonPressedListenerList == null) {
    buttonPressedListenerList=new ArrayList<FieldConfigStringButtonInterface>();
  }
  buttonPressedListenerList.add(listener);
}

public void addButtonPressedListener ( FieldConfigStringButtonInterface listener ) { if ( buttonPressedListenerList == null ) { buttonPressedListenerList = new ArrayList < FieldConfigStringButtonInterface > ( ) ; } buttonPressedListenerList . add ( listener ) ; }
adds the button pressed listener .
