On Wed, Jun 23, 2010 at 12:26 PM, jonat...@mugginsoft.com <jonat...@mugginsoft.com> wrote: > > On 23 Jun 2010, at 19:50, Kyle Sluder wrote: >> >> To describe it a bit more visually, here's a diagram of our view hierarchy: >> >> Scroll View >> |- Clip View >> |- Accessory view >> |- Document view >> >> Calling -enclosingScrollView on the accessory view returns nil. I >> believe that it should return the scroll view. >> >> One of the workarounds we're mulling over is to replace NSView's >> implementation of -enclosingScrollView to return the scroll view if >> the receiver is a descendant of the clip view. This makes sense to me, >> because I can't see a situation in which one would call >> -enclosingScrollView without the intent of obtaining "the scroll view >> that is responsible for scrolling me around." But since we don't have >> the source to AppKit, we can't be sure that AppKit doesn't rely on >> this behavior. >> > Perhaps: > > Define a -scrollViewSibling property/outlet on the accessory view and point > it to the document view. > > The NSView -enclosingScrollView override can check for a response to > scrollViewSibling and > conditionally send -enclosingScrollView to it. > > That way you are only overriding the -enclosingScrollView behaviour for views > whose response is considered defective.
We're doing this now (actually, we can't use an outlet because this is a view class in a framework, but the result is the same; we ask the document view for its -enclosingScrollView). I've also added a debug-only override of -[NSView enclosingScrollView] to trap all occasions where someone calls -enclosingScrollView and it returns nil, even though I think it should return an NSScrollView. It turns out that one of the places this happens is when layer-backed views set up their layers. I'm wondering if that has any bearing on some of the bugs we've seen with layer-backed views in scroll views. Perhaps the authors of that code harbored the same assumptions about -enclosingScrollView that I did. --Kyle Sluder _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
