Question

I try to do the following simple thing:

NSArray * entities = [context executeFetchRequest:inFetchRequest error:&fetchError];

Nothing fancy. But this freezes in iOS 5, it works fine in iOS 4. I don’t get exceptions, warnings or errors; my app just simply freezes.

Please help me out! I’m dying here! 😉

Answer 1

Thanks for the hints given in this page on how to solve this freezing issue which appeared on upgrading from iOS4. It has been the most annoying problem I have found since I started programming on iOS.

I have found a quick solution for cases where there are just a few calls to the context from other threads.

I just use performSelectorOnMainThread:

    [self performSelectorOnMainThread:@selector(stateChangeOnMainThread:) withObject: [NSDictionary dictionaryWithObjectsAndKeys:state, @"state", nil] waitUntilDone:YES];

To detect the places where the context is called from another thread you can put a breakpoint on the NSLog on the functions where you call the context as in the following piece of code and just use performSelectorOnMainThread on them.

if(![NSThread isMainThread]){
     NSLog(@"Not the main thread...");
}

I hope that this may be helpful…