question: @ Override public void onViewPositionChanged ( View changedView , int left , int top , int dx , int dy ) { super . onViewPositionChanged ( changedView , left , top , dx , dy ) ; float fractionScreen ; switch ( draggerView . getDragPosition ( ) ) { case TOP : case BOTTOM : dragOffset = Math . abs ( top ) ; fractionScreen = ( float ) dragOffset / draggerListener . dragVerticalDragRange ( ) ; break ; case LEFT : case RIGHT : default : dragOffset = Math . abs ( left ) ; fractionScreen = ( float ) dragOffset / draggerListener . dragHorizontalDragRange ( ) ; break ; } if ( draggerListener != null ) { draggerListener . onViewPositionChanged ( fractionScreen >= 1 ? 1 : fractionScreen ) ; } }
target:  Override method used notify the drag value based on position and dragRange