Detect when a presented view controller is dismiss

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

If you override on the view controller being dimissed:

override func removeFromParentViewController() {
    super.removeFromParentViewController()
    // your code here
}

At least this worked for me.