How to detect that the HorizontalScrollView has reached an end

Question

i want when reach to end ,the right button will change color ,when reach to the begin,the left button will change color ,so ,i want to ask how to detect that the HorizontalScrollView has reached an end.

Answer 1

    maxScrollX = horizontalScrollView.getChildAt(0).getMeasuredWidth()-horizontalScrollView.getMeasuredWidth(); 
    if (horizontalScrollView.getScrollX() == 0) { 
        lImageView.setImageResource(R.drawable.left_green); 
    } else { 
        lImageView.setImageResource(R.drawable.left); 
    }

    if (horizontalScrollView.getScrollX() == maxScrollX) { 
        rImageView.setImageResource(R.drawable.right_green); 
    } else { 
        rImageView.setImageResource(R.drawable.right); 
    }