Re: NSArrayController in entity mode and permutations (CoreData question)
Re: NSArrayController in entity mode and permutations (CoreData question)
- Subject: Re: NSArrayController in entity mode and permutations (CoreData question)
- From: vincent habchi <email@hidden>
- Date: Tue, 13 Apr 2010 21:51:06 +0200
Le 12 avr. 2010 à 23:17, Quincey Morris a écrit :
> I think I'm confused now about what scenario we are talking about. Are you saying that the object you insert with [NSArrayController insertObject...] is *not* a NSManagedObject, but is a proxy object that is linked to the NSManagedObject? Or are you referring to the NSArrayController itself as a proxy object?
Forget that story of proxies that was a botch. I reverted to the first scheme, followed your idea to implement a NSNumber attribute and a sort predicate. Well, it took me a whole day to figure out a clean algorithm to handle the renumbering caused by the drag-and-drop operation, but it works now, and is not plagued by any side effect anymore.
If you want to know a bit more, the managed object represents a "geographical data layer" (e.g.: roads, buildings, rivers, etc.). The user selects which gets drawn first, then which gets drawn over the first, etc. up to the highest layer, that lies atop all the others. This "ordered stack" is displayed on screen through a NSCollectionView whose contents observe the NSArrayController arrangedObjects. The user can drag and drop the NSView in the NSCollectionView to modify the drawing order.
Thanks a lot for your precious help, you and Kyle.
Vincent_______________________________________________
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