How to observe NSScroller changes?

Question

I have an NSScrollView subclass and I would like to update another NSView based on the current scroll position. I tried KVC-observing the val

Answer 1

Tell the scroll view's content view to post bounds changed notifications, then listen for NSViewBoundsDidChangeNotification.

[[aScrollView contentView] setPostsBoundsChangedNotifications:YES];
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(boundsDidChangeNotification:)
                                             name:NSViewBoundsDidChangeNotification
                                           object:[scrollView contentView]];

As stated in the Scroll View Programming Guide, you can get the current scroll position this way:

NSPoint currentScrollPosition = [[theScrollView contentView] bounds].origin;