CODEWITHSUNDEEP
ioscallbackviewcontroller
Andrew Duncan
Andrew Duncan

Reputation: 3753

PresentViewController completion block called too soon

I am modally presenting a ViewController from another one. The completion block is being called immediately, while the presented VC is still presented. Why would that be? Code follows.

UIStoryboard* sb = [UIStoryboard storyboardWithName:...];
UINavigationController* nc = [sb instantiateViewController...];
nc.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
[self presentViewController:nc
                   animated:YES
                 completion:^{ /* Called immediately! */ }];

There is stuff I want to do only when the presented VC is finished. I have a workaround but my understanding is I should be able to do it in the completion block.

Upvotes: 1

Views: 2621

Answers (2)

Andrew Duncan
Andrew Duncan

Reputation: 3753

OK I had RTFM and saw this: "completion: The block to execute after the presentation finishes." Which really does imply what I thought. Ambiguous at best.

HOWEVER... elsewhere we read "The completion handler is called after the viewDidAppear: method is called on the presented view controller." Which is quite another thing, and confirms Ian.

So my workaround is actually the right way to do it...

Upvotes: 0

Bay Phillips
Bay Phillips

Reputation: 2045

The completion block is called once the viewController has been presented, as per Apple's documentation. This is the intended behavior: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIViewController_Class/index.html#//apple_ref/occ/instm/UIViewController/presentViewController:animated:completion:

I'd suggest wiring up some sort of callback in your viewController's viewWillDissappear to perform an action if necessary.

Upvotes: 0

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