On Aug 13, 2014, at 11:31 , Luc Van Bogaert <luc.van.boga...@me.com> wrote:
> My question now is , where I should remove MyView as an observer with > 'self.model removeObserver: self forKey: @"property"...' '? > I tried to do this in 'dealloc', but it seems that from time to time my model > object is pulled right from under my when I close the document window, > resulting in an error stating that MyModel was deallocated while it still had > observers attached to it. Yes, this behavior is a consequence of the fact that the view’s “model” property is weak, and therefore not KVO compliant. (It can change to nil without anyone getting notified.) One way to handle this is to implement the window delegate method ‘windowWillClose:’ in your window controller, and use that to inform the view that it should stop observing the model. Unfortunately, there’s one other case you probably need to handle — what happens when the model is deallocated for some other reason. It’s possible that this isn’t possible in your app, but consider what happens if the user reverts the document, and the document object handles that by re-reading the document file and creating a new model. (I *think* that’s what happens if you don’t have any revert-handling code of your own.) In that case , the view’s weak “model” property will change to nil, which isn’t very useful. The upshot of this is that you’ll likely have a model-monitoring slab of code in your window controller, which is responsible for keeping the view up to date. Then, you’d probably use this mechanism to get the model reference to the view initially, rather than having the custom initializer. Or, you’d change the view to observe a “model” property of the window controller, which itself is derived from the document’s “model” property. But the details will vary depending on the details of your app. _______________________________________________ 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
