CODEWITHSUNDEEP
ios
ajrlewis
ajrlewis

Reputation: 3058

Why can't you set the modalPresentationStyle during the transition?

i have 2 view controllers, VCA and VCB. I transition from VCA to VCB with presentViewController(VCB, animated: true, completion: nil) and got back with dismissViewControllerAnimated(true, completion: nil) in VCB. This transition is managed by a custom TransitionManager instance with both VCA and VCB having their own TransitionManager instance as their transitioningDelegate's.

I want VCB to be presented over the top of VCA so in VCB's initialiser I add:

convenience init() {
    self.init()
    modalPresentationStyle = .OverFullScreen
}

This works.

However, if I remove modalPresentationStyle = .OverFullScreen from VCB's initialiser, and try to set it in the TransitionManager class in the UIViewControllerAnimatedTransitioning delegate as follows

func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
    let transitionContext: UIViewControllerContextTransitioning!
    let toVC = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)!
    toVC.modalPresentationStyle = .OverFullScreen

    // do animation ...
}

the effect doesn't work. Why is this the case, please?

Edit

It seems that modalPresentationStyle.rawValue is 0 (.FullScreen) in VCB's viewDidLoad and then 5 (the wanted value, OverFullScreen) in VCB's viewDidAppear.

Upvotes: 1

Views: 1469

Answers (1)

ajrlewis
ajrlewis

Reputation: 3058

Apple documentation states To change the transition type, you must set this property before presenting the view controller.

Upvotes: 1

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