question: @ Override public int clampViewPositionVertical ( View child , int top , int dy ) { int topBound = 0 ; int bottomBound = 0 ; switch ( draggerView . getDragPosition ( ) ) { case TOP : if ( top > 0 ) { topBound = draggerView . getPaddingTop ( ) ; bottomBound = ( int ) draggerListener . dragVerticalDragRange ( ) ; } break ; case BOTTOM : if ( top < 0 ) { topBound = ( int ) - draggerListener . dragVerticalDragRange ( ) ; bottomBound = draggerView . getPaddingTop ( ) ; } break ; default : break ; } return Math . min ( Math . max ( top , topBound ) , bottomBound ) ; }
target:  Return the value of slide based on top and height of the element