boolean pageScroll(int direction){
  int nextPage=-1;
  if (direction == FOCUS_UP) {
    nextPage=Math.max(0,mSelectedPosition - getChildCount() - 1);
  }
 else   if (direction == FOCUS_DOWN) {
    nextPage=Math.min(mItemCount - 1,mSelectedPosition + getChildCount() - 1);
  }
  if (nextPage >= 0) {
    setSelectionInt(nextPage);
    invokeOnItemScrollListener();
    return true;
  }
  return false;
}

boolean pageScroll ( int direction ) { int nextPage = - 1 ; if ( direction == FOCUS_UP ) { nextPage = Math . max ( 0 , mSelectedPosition - getChildCount ( ) - 1 ) ; } else if ( direction == FOCUS_DOWN ) { nextPage = Math . min ( mItemCount - 1 , mSelectedPosition + getChildCount ( ) - 1 ) ; } if ( nextPage >= 0 ) { setSelectionInt ( nextPage ) ; invokeOnItemScrollListener ( ) ; return true ; } return false ; }
scrolls up or down by the number of items currently present on screen .
