@Override
    public int computeVerticalScrollRange() {
        final int count = getChildCount();
        final int contentHeight = getHeight() - getPaddingBottom() - getPaddingTop();
        if (count == 0) {
            return contentHeight;
        }

        int scrollRange = getChildAt(0).getBottom();
        final int scrollY = getScrollY();
        final int overscrollBottom = Math.max(0, scrollRange - contentHeight);
        if (scrollY < 0) {
            scrollRange -= scrollY;
        } else if (scrollY > overscrollBottom) {
            scrollRange += scrollY - overscrollBottom;
        }

        return scrollRange;
    }
<p>The scroll range of a scroll view is the overall height of all of its
children.</p>
@hide
app/src/main/java/home/smart/fly/animations/widget/NestedScrollView.java