I've wanted to learn how to create cool transitions between view controllers for a long time now, so recently I set out to do that by recreating a couple of transitions that I like from two apps: Instagram and Pinterest.
Tap a cell to present a view controller using the corresponding transition. Tap the button on the top left corner to dismiss it, or swipe from the left edge of the screen to dismiss it interactively!
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The architecture is pretty simple. The main view is a TransitionCollectionViewController instance, which consists of a collection view where each cell represents one of the implemented transitions. Tapping a cell will present a TransitionViewController instance using the corresponding transition.
Before presenting the view controller, its transitioningDelegate property is set to a TransitionManager instance. This class conforms to the UIViewControllerTransitioningDelegate protocol, and therefore is responsible for providing UIKit with the objects to use for animating the presentation and dismissal of the view controller.
There are two animation controllers for each transition, one for animating the presentation and another for animating the dismissal. All animation controllers conform to the UIViewControllerAnimatedTransitioning protocol. Currently there's one interaction controller for all transitions, DismissInteractionController, which makes the dismissal interactive. This class conforms to the UIPercentDrivenInteractiveTransition protocol.
Both TransitionCollectionViewController and TransitionViewController conform to the TransitionAnimatable protocol so that they can be queried by the animation controllers for properties such as the frames of their image views, and be notified of events such as an animation starting or ending.
- UIViewControllerTransitioningDelegate | Apple Developer Documentation
- Custom UIViewController Transitions: Getting Started | Kodeco
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