android - How to check whether ScrollView is scrollable

Question

I was wondering, how to check whether the current ScrollView is scrollable? It seems that, there isn't public method called canScroll or isScrollable in ScrollView.

Scrollable : You can move the ViewGroup inside the ScrollView up and down, and the scroll bar will be visible when you move it up and down. So, if there is only little rows in the ScrollView, and they can fit inside single screen, ScrollView is not scrollable then.

Answer 1

You can do some little math to calculate the views raw height and the height of the content. If the difference of this heights is < 0 the view is scrollable.

To calculate the raw height you can use View.getMeasuredHeight(). Because ScrollView is a ViewGroup and has max one child, get the height of that child with ViewGroup.getChildAt(0).getHeight();

Use a ViewTreeObserver to get the heights, because it will be called at the moment the layout / view is changing the visibility, otherwise the heights could be 0.

ScrollView scrollView = (ScrollView)findViewById(R.id...);
ViewTreeObserver observer = scrollView.getViewTreeObserver();
observer.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        int viewHeight = scrollView.getMeasuredHeight();
        int contentHeight = scrollView.getChildAt(0).getHeight();
        if(viewHeight - contentHeight < 0) {
            // scrollable
        }
    }
});