But what managed object are you dealing with? Is the Asset a managed object? If so, you can only access its properties from the queue of its managed object context. So if it is a main queue context, you can only access the MO’s properties from the main queue. If it is a private queue context, you use performBlock on the MO’s context to execute a block of code in the context’s queue and you must access the MO’s properties from inside that block. If I’m stating something you already know, forgive me. It is not clear from your post. Example code would help.
> On Oct 27, 2016, at 11:24 PM, Steve Mills <sjmi...@mac.com> wrote: > > On Oct 27, 2016, at 19:00:14, Dave Fernandes <dave.fernan...@utoronto.ca> > wrote: >> >> Are you accessing the properties from within a >> NSManagedObjectContext.performBlock block? Sounds like you may be accessing >> the managed objects from the wrong queue. > > I'll explain what's going on. Each NSCollectionViewItem in the > NSCollectionView is being assigned its representedObject (the Asset, which is > a reference to an image file). At that point, I ask the Asset to > requestPreviewImageAtSize:, which creates an NSBlockOperation (and adds it to > an NSOperationQueue), whose block creates a CGImageSourceRef. Before it can > create the CGImageSourceRef, it needs to get the url. It does this by asking > for its .folder and .name properties. Those are nonatomic properties of the > Asset. Once it has the url and the CGImageSourceRef, it creates the > CGImageRef, converts that to an NSImage, and finally assigns that to the > Asset's atomic .thumb property. > > The folder and name properties were generated by mogenerator, a tool for > creating document model classes for CoreData .xcdatamodeld files. The thumb > property is something I added manually to cache the thumbnail, and the > AssetItemView's NSImageView's Value binds to it as well. > > So I'm not directly dealing with any NSManagedObjectContext here. That's all > taken care of when the items are added to it or when a document is opened. > All I'm doing is generating a preview for each managed object. > > -- > Steve Mills > Drummer, Mac geek _______________________________________________ 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
