isBeingDismissed not set in viewWillDisappear:

Question

I have some code to clean up in my viewWillDisappear:, which I only want to use when the view is moving back to the parent view controller.

- (void)         


        

Answer 1

As @Yuval Tal mentioned, this flag does not work when you're dismissing controller that is embeded inside navigation controller. Here's an extension that I use:

extension UIViewController 
{
    var isAboutToClose: Bool {
        return self.isBeingDismissed ||      
               self.isMovingFromParentViewController ||          
               self.navigationController?.isBeingDismissed ?? false
    }
}

It can be easily extended when you find another case when standard .isBeingDismissed won't work. And if you find, let us, let me know in comments.

Answer 2

Your issue is how you are dismissing your modal view. How is rootViewController being defined?

When I call [self dismissModalViewControllerAnimated:YES] then [self isBeingDismissed] evaluates to true.

When I call [parentViewController dismissModalViewControllerAnimated:YES] then [self isBeingDismissed] evaluates to true, whereby parentViewController is the UIViewController that presented the modal view (note: not a UINavigationController).

Answer 3

If this is the first view controller in a modal navigation controller that's being dismissed, calling self.isBeingDimissed() from viewWillDisappear: returns false.

However, since the entire navigation controller is being dismissed, what actually works is self.navigationController?.isBeingDismissed(), which returns true.

Answer 4

        viewController.isBeingPresented == NO;
        [rootVC presentViewController:viewController animated:NO completion:^{
            viewController.isBeingPresented == NO;
            viewController.isBeingDismissed == NO;
            [viewController dismissViewControllerAnimated:NO completion:^{
                viewController.isBeingDismissed == NO;
            }];
            viewController.isBeingDismissed == NO;    // is not work
        }];
        viewController.isBeingPresented == YES;     // is work

        viewController.isBeingPresented == NO;
        [rootVC presentViewController:viewController animated:NO completion:^{
            viewController.isBeingPresented == NO;
            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
                viewController.isBeingDismissed == NO;
                [viewController dismissViewControllerAnimated:NO completion:^{
                    viewController.isBeingDismissed == NO;
                }];
                viewController.isBeingDismissed == YES;    // is work
            });
        }];
        viewController.isBeingPresented == YES;     // is work

Answer 5

If by some chance you came here trying to use isBeingDismissed on a non-modally presented view controller, you can always check the topViewController property of your navigationController, for instance:

if navigationController?.topViewController != self {
    return
}