Unbalanced calls to begin/end appearance transitions for <UITabBarController: 0x197870>

Question

Without seeing more of the surrounding code I can't give a definite answer, but I have two theories.

1. You're not using UIViewController's designated initializer initWithNibName:bundle:. Try using it instead of just init.

2. Also, self may be one of the tab bar controller's view controllers. Always present view controllers from the topmost view controller, which means in this case ask the tab bar controller to present the overlay view controller on behalf of the view controller. You can still keep any callback delegates to the real view controller, but you must have the tab bar controller present and dismiss.

I fixed this error by changing animated from YES to NO.

From:

[tabBarController presentModalViewController:viewController animated:YES];

To:

[tabBarController presentModalViewController:viewController animated:NO];

As posted by danh

You can generate this warning by presenting the modal vc before the app is done initializing. i.e. Start a tabbed application template app and present a modal vc on top of self.tabBarController as the last line in application:didFinishLaunching. Warning appears. Solution: let the stack unwind first, present the modal vc in another method, invoked with a performSelector withDelay:0.0

Try to move the method into the viewWillAppear and guard it so it does get executed just once (would recommend setting up a property)

Another solution for many cases is to make sure that the transition between UIViewControllers happens after the not-suitable (like during initialization) procedure finishes, by doing:

__weak MyViewController *weakSelf = self;
dispatch_async(dispatch_get_main_queue(), ^{
    [weakSelf presentViewController:vc animated:YES];
});

This is general for also pushViewController:animated:, etc.