picciano picciano - 5 months ago 594
iOS Question

Attempting to load the view of a view controller while it is deallocating ... UIAlertController

I am building with the release version of Xcode 7.0. No storyboards, just nib files.

I have a single

UINavigationController
created by the app delegate and initialize it with a view controller.

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
UIViewController *viewController = [[TGMainViewController alloc] initWithNibName:nil bundle:nil];
self.navigationController = [[UINavigationController alloc] initWithRootViewController:viewController];
self.navigationController.navigationBar.barStyle = UIBarStyleBlack;
self.navigationController.navigationBar.hidden = YES;
self.window.rootViewController = self.navigationController;
[self.window makeKeyAndVisible];


After navigating to a new view using:

TGRoutePreparationViewController *viewController = [[TGRoutePreparationViewController alloc] initWithNibName:nil bundle:nil];
[self.navigationController pushViewController:viewController animated:YES];


Then going back using:

[self.navigationController popViewControllerAnimated:YES];


I receive the following error:

Attempting to load the view of a view controller while it is deallocating is not allowed and may result in undefined behavior (<UIAlertController: 0x7b29a600>)


While I do use
UIAlertController
s in the app, none are used or instantiated before receiving this error. This only happens when running under iOS 9.0. Running under iOS 8.4 produces no error. In all cases, the app appears to function normally and the navigation appears to be working.

I suspect the error is misleading, but how can I fix this?

Per @Nick, here is the dealloc method being used:

- (void)deregisterNotificationHandlers {
[[NSNotificationCenter defaultCenter] removeObserver:self];
}

- (void)dealloc {
[self deregisterNotificationHandlers];
}

Answer

I was finally able to track it down to a UIActionSheet class variable inside a third-party library, Mapbox GL.

I opened an issue with that dev team: https://github.com/mapbox/mapbox-gl-native/issues/2475

Partial credit (and an up vote and bounty) to @Aaoli for mentioning having a UIAlertView as a class variable.