Detect when a presented view controller is dismissed

Question

Let's say, I have an instance of a view controller class called VC2. In VC2, there is a "cancel" button that will dismiss itself. But I can't detect or receive any callback when the "cancel" button got trigger. VC2 is a black box.

A view controller (called VC1) will present VC2 using presentViewController:animated:completion: method.

What options does VC1 have to detect when VC2 was dismissed?

Edit: From the comment of @rory mckinnel and answer of @NicolasMiari, I tried the following:

In VC2:

-(void)cancelButton:(id)sender {     [self dismissViewControllerAnimated:YES completion:^{      }]; //    [super dismissViewControllerAnimated:YES completion:^{ //         //    }]; } 

In VC1:

//-(void)dismissViewControllerAnimated:(BOOL)flag completion:(void (^)(void))completion - (void)dismissViewControllerAnimated:(BOOL)flag                            completion:(void (^ _Nullable)(void))completion {     NSLog(@"%s ", __PRETTY_FUNCTION__);     [super dismissViewControllerAnimated:flag completion:completion]; //    [self dismissViewControllerAnimated:YES completion:^{ //         //    }]; } 

But the dismissViewControllerAnimated in the VC1 was not getting called.

Answer 1

There is a special Boolean property inside UIViewController called isBeingDismissed that you can use for this purpose:

override func viewWillDisappear(_ animated: Bool) {     super.viewWillDisappear(animated)     if isBeingDismissed {         // TODO: Do your stuff here.     } }