On Fri, Apr 8, 2011 at 8:27 AM, Matt Neuburg <m...@tidbits.com> wrote:
> On Thu, 07 Apr 2011 07:15:20 -0400, Jeffrey Walton <noloa...@gmail.com> said:
>>Hi All,
>>
>>I have a UIViewController as follows. Its just an "About Box", with a
>>navigation bar and button (to cancel) and two labels.
>>
>>The controller was built with Interface Builder. The Navigation Bar
>>and two labels are IBOutlets. According to IB, they are properly
>>connected. I did not know what to connect the Navigation Items outlet
>>to, so they are currently unconnected (formerly, they were connected
>>to File's Owner which did not help).
>>
>>+ File's Owner
>>+ First Responder
>>+ View
>> + Navigation Bar
>> + Navigation Item (Title)
>> + Bar Button
>> + Label 1
>> + Label 2
>>
>>When the app starts, I tap a button and bring up the About box. Then I
>>dismiss it. That is it.
>>
>>When the view is dismissed by tapping Cancel, NSZombie reports:
>> -[UINavigationBar willMoveToSuperview:]: message sent to
>>deallocated instance
>
> You're posing your question very oddly, since you say "I have a
> UIViewController" but then you never show anything about any view controller.
> Thus it is impossible to say what you actually have. How does this view
> controller get instantiated? Who is retaining it? (If no one, then it and the
> whole kit and caboodle it loads from the nib could just vanish in a puff of
> smoke.) It has to be someone's job to retain the view controller, and it is
> the view controller's job to retain its view (which it will do if you are
> loading the nib correctly, but you don't show that, so who's to say?). Since
> everything else is inside the view, it is retained automatically.
>
> It sounds a little like you're confused between outlets and memory
> management. They really don't have much to do with each other. Outlets are
> ways of getting references and setting instance variables as a nib loads.
> Memory management is, uh, memory management. I mean, sure, you might need an
> outlet to something in order to be able to refer to it in order to manage its
> memory, but they are still different worlds of thought. The only item in the
> nib that you should be managing the memory of is the View, because it's a
> top-level object - and the view controller should be doing that, assuming
> that the First Responder is of the view controller's class and assuming that
> the view controller's view outlet is connected to the View and assuming that
> you're loading the nib correctly...
>
> Anyway, the CALayer is surely a total red herring.
>
> m.
>
Thanks to all who responded. I tried to build a minimal test case
which reproduced the problem - no joy (the test code worked fine).
The problem was prefixing the various IBOutlets with "self.". To add
insult to injury, I added "self." to nearly all interface variables to
ensure disambiguation when I first encountered EXC_BAD_ACCESS.
According to Hillegass, "self" is equivalent to "this". So I'm not
sure what is going on with the dot operator (or I don't have the
correct understanding in Obj C).
Jeff
The difference between the test case and the real code was:
*** Test code ***
- (void) dealloc
{
// OK???
[navigationBar release];
navigationBar = nil;
[dismissButton release];
dismissButton = nil;
[super dealloc];
}
*** Real code ***
#define SAFE_RELEASE(x) { ASSERT(x); if((x) != nil) { [(x) release],
(x) = nil; } }
#define QUIET_RELEASE(x) { if((x) != nil) { [(x) release], (x) = nil; } }
- (void) dealloc
{
// Crash
QUIET_RELEASE(self.navigationBar);
QUIET_RELEASE(self.dismissButton);
...
[super dealloc];
}
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