Re: [RESOLVED] Re: Curious about copyWithZone message from NSArrayController in "GC required" project
Re: [RESOLVED] Re: Curious about copyWithZone message from NSArrayController in "GC required" project
- Subject: Re: [RESOLVED] Re: Curious about copyWithZone message from NSArrayController in "GC required" project
- From: Luke Evans <email@hidden>
- Date: Thu, 14 Feb 2008 16:43:03 -0800
Closure:
Not that this is necessarily of any use to anyone, but the "something
seriously wrong" causing -copyWithZone to be sent to an
NSManagedObject was the following:
I had an NSArrayController set up to collect a set of NSManagedObjects
from a master view selection 'upstream'. I had then bound a table
view to this in one of its columns, *but* I had only set the
Controller Key (to arrangedObjects), I had not entered a Model Key
Path i.e. set up a path to the content to be rendered in each cell of
the column.
Under these circumstances, the objects referenced in arrangedObjects
(which happen to be Core Data objects) get sent a -copyWithZone.
So this is why the problem "went away" when I had restructured my
bindings before, I had clearly 'done the right thing' and the problem
vanished. I've just repeated the earlier mistake and so can report
the reason for the message.
-- Lwe
On 13-Jan-08, at 3:37 PM, Luke Evans wrote:
O.K...
So, I just did this and found it wasn't being called any longer.
So, I suspect your original intuition was right - there was
something badly wrong with my code (which thankfully I have now
rectified - though its frustrating not to be able to nail the
original reason now).
One change that may have had a bearing here was that I had
inadvertently commented out some code to return an
NSCollectionViewItem in a subclass of NSCollectionView that was
generating UI for the B objects. I fixed this yesterday. It's
possible that something in NSCollectionView was trying to do its
best with just the prototype item and the list of B's from the
NSArrayController. Anyway, that's pure speculation, and perfectly
well covered by your comment that "something is seriously wrong with
your code"!
I'm deleting the spurious copyWithZone now, safe in the knowledge
that it's just not something that I should need to implement until
such time as I have a real need for a copy constructor in that class.
Thanks.
-- Lwe
On 13-Jan-08, at 2:54 PM, Bill Bumgarner wrote:
You mentioned that you had implemented a -copyWithZone: on B? Can
you set a breakpoint on that and see what backtrace barfs up as a
result?
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