I'm trying to create a custom transition for a modally presented view controller using UIViewControllerTransitioningDelegate, UIViewControllerAnimatedTransitioning and UIPresentationController.
In my presenting view controller I implement UIViewControllerTransitioningDelegate and have the following methods:
-(id<UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented
presentingController:(UIViewController *)presenting
sourceController:(UIViewController *)source {
return [[MyAnimationController alloc] initWithAnimationType:MyAnimationTypePresent];
}
- (id<UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed {
return [[MyAnimationController alloc] initWithAnimationType:MyAnimationTypeDismiss];
}
- (UIPresentationController *)presentationControllerForPresentedViewController:(UIViewController *)presented
presentingViewController:(UIViewController *)presenting
sourceViewController:(UIViewController *)source {
return [[MyPresentationController alloc] initWithPresentedViewController:presented presentingViewController:presenting];
}
Now in my subclass of UIPresentationController I add a dimming view beneath the presented view controller and want to fade it in along with the appearance transition.
- (void)presentationTransitionWillBegin {
self.dimmingView.alpha = 0.0f;
[self.containerView insertSubview:self.dimmingView atIndex:0];
[self.dimmingView autoPinEdgesToSuperviewEdges];
[self.presentedViewController.transitionCoordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> _Nonnull context) {
self.dimmingView.alpha = 1.0f;
}
completion:nil];
}
- (void)dismissalTransitionWillBegin {
[self.presentedViewController.transitionCoordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> _Nonnull context) {
self.dimmingView.alpha = 0.0f;
}
completion:^(id<UIViewControllerTransitionCoordinatorContext> _Nonnull context) {
[self.dimmingView removeFromSuperview]; }];
}
The interesting - and quite frustrating - thing is that the presentation and dismissal animations for my presented view controller work as expected and as implemented in MyAnimationController. As for the fade-in/out of my dimming view, it only works when dismissing the presented view controller. When presenting it, the fade-in is not animated alongside the transition but simply uses a fixed amount of time. I'm pretty sure I implemented everything according to Apple's documentation and several tutorials but for some reason it simply won't work as expected. Any suggestion as to what the issue might be here?
