code: private void initializeScrollAnimator() {
  		ScrollAnimator scrollAnimator = new ScrollAnimator(button_menu, new ObjectAnimatorFactory());
  		scrollAnimator.configureListView(lv_contacts);
  		scrollAnimator.setDurationInMillis(300);
  	}
docs: Initialize ScrollAnimator to work with ButtonMenu custom view, the ListView used in this sample and an
  animation duration of 200 milliseconds.