UIPickerView, detect “rolling wheel” start and stop?

Question

I just discovered that if I do the following:

1. Click the button that animates a UIPickerView into my view
2. Quickly start the wheel rolling

Answer 1

As animation keys don't work, I wrote this simple function that works for detecting if a UIPickerView is currently moving.

-(bool) anySubViewScrolling:(UIView*)view
{
    if( [ view isKindOfClass:[ UIScrollView class ] ] )
    {
        UIScrollView* scroll_view = (UIScrollView*) view;
        if( scroll_view.dragging || scroll_view.decelerating )
        {
            return true;
        }
    }

    for( UIView *sub_view in [ view subviews ] )
    {
        if( [ self anySubViewScrolling:sub_view ] )
        {
            return true;
        }
    }

    return false;
}

It ends up returning true five levels deep.