@Override
 public Parcelable onSaveInstanceState() {
   Parcelable superState = super.onSaveInstanceState();
   SavedState ss = new SavedState(superState);
   ss.prevFirstVisiblePosition = mPrevFirstVisiblePosition;
   ss.prevFirstVisibleChildHeight = mPrevFirstVisibleChildHeight;
   ss.prevScrolledChildrenHeight = mPrevScrolledChildrenHeight;
   ss.prevScrollY = mPrevScrollY;
   ss.scrollY = mScrollY;
   ss.childrenHeights = mChildrenHeights;
   return ss;
 }