In App Purchase/View Controller Crash: Message sent to deallocated instance - iphone

Question

I have a button on my view controller that presents my In App Purchases store.
storeSinglePlayer *ssp = [[storeSinglePlayer alloc] initWithNibName:#"storeSinglePlayer" bundle:nil];
//Animation Code
CATransition* transition = [CATransition animation];
transition.duration = 0.5;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionPush;
transition.subtype = kCATransitionFromTop;
[self.navigationController.view.layer addAnimation:transition forKey:nil];
[self.navigationController pushViewController:ssp animated:NO];
The navigation controller successfully pushes this store on the screen. The store has a back button which executes the following code:
[self.request cancel];
self.request.delegate = nil;
self.request = nil;
[[SKPaymentQueue defaultQueue] removeTransactionObserver:self];
CATransition* transition = [CATransition animation];
transition.duration = 0.5;
transition.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
transition.type = kCATransitionPush;
transition.subtype = kCATransitionFromBottom;
[self.navigationController.view.layer addAnimation:transition forKey:nil];
[self.navigationController popViewControllerAnimated:NO];
This executes successfully as well. But if I now click the button to show the store view controller again, I get the message:
-[storeSinglePlayer respondsToSelector:]: message sent to deallocated instance 0xd642df0
This is a very famous problem indeed. And as you'll notice in the code above, I have incorporated the suggestions I came across various posts on stackoverflow. The following code has been implemented:
[self.request cancel];
self.request.delegate = nil;
self.request = nil;
[[SKPaymentQueue defaultQueue] removeTransactionObserver:self];
Also I have my property and corresponding synthesize set as:
#property (nonatomic, strong) SKProductsRequest *request;
#synthesize request = _request;
I have no clue, why is it crashing!
P.S: The project is ARC enabled.

Answer 1

Something is calling your ssp after it has been released by ARC. The code you posted doesn't make it clear where that is happening.
One thing that most likely would solve the problem would be to keep a reference with a member variable+property to your ssp in your class declaration, instead of createing a new one every time you click the button. Just init it once when your first viewcontroller loads and reuse it instead.
If you want to investigate further, you could try to comment out the blocks setting up the transition and see if it still crashes. Maybe the navigationcontroller makes some call after the ssp has been released.

Answer 2

When a message is sent to a deallocated instance, an object was released from the memory and you are attempting to use it again. ARC must be releasing the object since it is automatically detecting that you no longer need the it. Try adding one of the following to your header file.
#property (nonatomic, strong) storeSinglePlayer *ssp;
or
storeSinglePlayer *__strong ssp;
The important word above is strong. It tells ARC that you want to retain this object for later use.

Answer 3

I got where I was messing up. I was handling multiple rotations using the following code:
[[NSBundle mainBundle] loadNibNamed:[NSString stringWithFormat:#"storeSinglePlayerLandscape"] owner:self options:nil];
[self viewDidLoad];
I realize now, this not the best practice, as it calls viewDidLoad multiple times. Still, that's not really the cause of the problem. It works fine, when the store is displayed only a few times and returned back to the previous view controller. But say after 10-15 times, there are too many requests which would return with the product and hence send the error , "message sent to deallocated instance".
I commented out the code, and it works fine now.
I know, this is a very typical problem, which most users might not face. But just in case, you used implemented some bad code like me, may be this information works!