How do I catch when UIViewController displays after dismissViewControllerAnimated - objective-c

Question

I've got two UIViewControllers. I'm using modal segue to the second one, when coming back I use dismissViewControllerAnimated. I want to fire a method when I come back to the first one. How can I do that?
I tried to fire a custom notification before dismissViewControllerAnimated and catching it in the first UIViewController, but it doesn't catch anything, because it's still on the second one when it's fired.

Answer 1

There are easy options I can see.
Use the viewDidDisappear: method in the view you're dismissing.
dismissViewControllerAnimated:completion: method accepts a block that actually executes after viewDidDisappear executes in the dismissing view.
To pass a reference from one view controller to the next:
In the second view controller's .h file, add a property:
#property (nonatomic,strong) FirstViewController *firstVC;
In your first view controller, add the following method:
- (void)prepareForSegue:(UIStoryboardSegue*)segue sender:(id)sender {
if([#"segue_YOUR_SEGUE_NAME" isEqualToString:[segue identifier]]) {
if([[segue destinationViewController] isKindOfClass:
[SecondViewController class]]) {
SecondViewController *dest = (SecondViewController*)[segue
destinationViewController];
dest.firstVC = self;
}
}
}
Now, in your second view controller, you can do two things, as I already stated:
[self dismissViewControllerAnimated:YES
completion:^{
[self.firstVC someMethod];
}];
OR...
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:animated];
[self.firstVC someMethod];
}