检查ScrollView是在底部，顶部还是侧面

Question

如何快速轻松地检查ScrollView或Horizo​​ntalScrollView是在其底部，顶部还是其一侧边缘？

Answer 1

As of API level 14 (Android 4.0 Ice Cream Sandwich), you can use View's methods canScrollHorizontally (int direction) and canScrollVertically (int direction) .

Example usage:

//Check if ScrollView is at the bottom
//If not, scroll to the top
if(scrollView.canScrollVertically(1))
    scrollView.post(new Runnable() {

            @Override
            public void run() {
                scrollView.fullScroll(View.FOCUS_UP);
            }

        });

You can use this on ListView as well. For example, when working with messaging app, you may want to check if user is reading older messages, so when he will receive a new one, he won't be disrupted by scrolling to the bottom, but rather keeping him at current position.