Re: Can an object observe itself?
Re: Can an object observe itself?
- Subject: Re: Can an object observe itself?
- From: Stuart Malin <email@hidden>
- Date: Sat, 7 Mar 2009 11:25:01 -1000
On Mar 7, 2009, at 11:18 AM, Keary Suska wrote:
On Mar 7, 2009, at 1:31 PM, Stuart Malin wrote:
I have a model class with multiple properties. I need to know in a
variety of places when certain of these change. Presently, the
model objects can be changed by an inspector that has bindings to
the model instances, which are managed as a collection by an
NSArrayController. So... I tried adding code to the model object to
observe itself (on a key that is a dependent key set up with
+setKeys:triggerChangeNitificationsForDependentKeys). I was then
going to have that observer issue a notification. However, the
model's -observeValueForKeyPath:ofObject:change:context: method
isn't getting called when I make changes. Thinking the problem was
with the dependent key, I changed to observe a specific key. That
doesn't work either. So I am wondering if an object can observe
itself. I add the observer in the model object's -init method,
after invoking -init on the superclass:
The main issue is that you have to remove observation before
deallocating. Otherwise an exception will be raised (Leopard) or you
will crash (Tiger and earlier).
Yes, I do remove the observer in -dealloc.
My problem was that I also created instances via NSCoding protocol
methods (-initWithCoder) and had not there set the observer in place,
and the source of my model objects was via that.
Thanks for your help and interest!
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