> On May 10, 2016, at 4:13 PM, Quincey Morris
> <[email protected]> wrote:
>
> On May 10, 2016, at 16:05 , Carl Hoefs <[email protected]
> <mailto:[email protected]>> wrote:
>>
>> I'm not sure how context is to be used here
>
> It has to be a value that’s unique to the piece of code that tests it. In
> effect, this means unique to the class that creates and responds to the
> observations. If you’re in Obj-C, the usual trick is to use the static
> address of something, like this:
>
>> static void* kvoContext = &kvoContext;
>
> This exploits a quirk of C to initialize the static variable as containing
> its own address. That means you can specify the ‘context:’ parameter as
> EITHER ‘kvoContext’ OR ‘&kvoContext’, so that forgetting the & is harmless.
>
>
Okay... It appears that for some odd reason, once in a blue moon, 'object' and
'keyPath' aren't what they're supposed to be, so I super it, and it blows.
- (void) observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
{
if ((object == uploadQueue) && [keyPath isEqualToString:@"operations"]) {
[self performSelectorOnMainThread:@selector(displayQueueInfo)
withObject:nil
waitUntilDone:NO];
} else {
[super observeValueForKeyPath:keyPath
ofObject:object
change:change
context:context];
}
}
I will set 'context' and use it in my check instead.
-Carl
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