question: private float overScrollUp ( int deltaY , int range ) { deltaY = Math . max ( deltaY , 0 ) ; float currentTopAmount = getCurrentOverScrollAmount ( true ) ; float newTopAmount = currentTopAmount - deltaY ; if ( currentTopAmount > 0 ) { setOverScrollAmount ( newTopAmount , true , false ) ; } float scrollAmount = newTopAmount < 0 ? - newTopAmount : 0.0f ; float newScrollY = mOwnScrollY + scrollAmount ; if ( newScrollY > range ) { if ( ! mExpandedInThisMotion ) { float currentBottomPixels = getCurrentOverScrolledPixels ( false ) ; setOverScrolledPixels ( currentBottomPixels + newScrollY - range , false , false ) ; } mOwnScrollY = range ; scrollAmount = 0.0f ; } return scrollAmount ; }
target:  Perform a scroll upwards and adapt the overscroll amounts accordingly