Question

Is there any way to know when a HorizontalScrollView gets to its right limit?

Answer 1

Yes, but first you will have to override the HorizontalScrollView class and provide your own listener. For some reason the SDK will not let you access the OnScrollChanged Listener directly.

Do the following:

public class FixedScrollView extends HorizontalScrollView
{
    private ScrollViewListener scrollViewListener = null;

    public FixedScrollView(Context context)
    {
        super(context);
    }

    public FixedScrollView(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
    }

    public FixedScrollView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
    }

    public void setScrollViewListener(ScrollViewListener scrollViewListener)
    {
        this.scrollViewListener = scrollViewListener;
    }

    @Override
    protected void onScrollChanged(int x, int y, int oldx, int oldy)
    {
        super.onScrollChanged(x, y, oldx, oldy);
        if (scrollViewListener != null)
        {
            scrollViewListener.onScrollChanged(this, x, y, oldx, oldy);
        }
    }

    public interface ScrollViewListener
    {
        void onScrollChanged(FixedScrollView scrollView, int x, int y, int oldx, int oldy);
    }
}

Then you can use this in your code as so:

FixedScrollView scrollView = (FixedScrollView) findViewById(R.id.scroller);

Set the onScrollChangeListener:

scrollView.setScrollViewListener(scrollerChanged);

And then do the following in the listener to detect the edges:

ScrollViewListener scrollerChanged = new ScrollViewListener()
    {

        @Override
        public void onScrollChanged(FixedScrollView scrollView, int x, int y, int oldx, int oldy)
        {
            int maxScrollX = scrollView.getChildAt(0).getMeasuredWidth() - scrollView.getMeasuredWidth();

            if (scrollView.getScrollX() == 0)
            {
                //Left side
            }
            else if (scrollView.getScrollX() == maxScrollX)
            {
                //Right side
            }
            else
            {
                //Neither left nor right
            }
        }
    };