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Re: Notifications and Subclassing
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Re: Notifications and Subclassing


  • Subject: Re: Notifications and Subclassing
  • From: Gordon Apple <email@hidden>
  • Date: Tue, 08 Mar 2011 11:28:09 -0600
  • Thread-topic: Notifications and Subclassing

Yup.  Right you are.  Thanks.

This was originally a singleton class where it wouldn't have shown up. That
changed in redesign when we started switching different subclasses, which
caused the problem.


On 3/8/11 10:07 AM, "glenn andreas" <email@hidden> wrote:

>
> On Mar 8, 2011, at 9:42 AM, Gordon Apple wrote:
>
>> Class A:  NSObject, has methods:
>>
>> -  (void)foo:(Notification*)notification {
>>    ...
>> }
>>
>> - (void)addObservers {
>>    [[NSNotificationCenter defaultCenter] addObserver:self
>>                                             selector:@selector(foo:)
>>                                                 name:notificationName
>>                                               object:nil];
>> }
>>
>>
>> Class B: subclass of A.  This is the class used.
>>
>> Notification sent from elsewhere.  Console:
>>
>> -[NSCFString foo:]: unrecognized selector sent to instance 0x69807c0
>>
>>
>> Is this due to confusion of of which class received the notification?  Or is
>> this a compiler/linker bug?  I even tried declaring foo in A¹s headers, to
>> no avail.  This same overall procedure is used elsewhere (without
>> subclassing), with no problems.  What am I missing?
>>
>>
>>
>
> That's a classic memory management problem.
>
> Most likely, you're forgetting to unregister your observer when you are
> deallocating it (resulting in a notification center to have a stale pointer
> that is later reused by an NSString).
>
>
> Glenn Andreas                      email@hidden
> The most merciful thing in the world ... is the inability of the human mind to
> correlate all its contents - HPL
>



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References: 
 >Re: Notifications and Subclassing (From: glenn andreas <email@hidden>)

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