# UIViewControllerInteractiveTransitioning A set of methods that enable an object (such as a navigation controller) to drive a view controller transition. ``` @MainActor protocol UIViewControllerInteractiveTransitioning : NSObjectProtocol ``` ## Overview An *interactive transition delegate* (which is the term for an object that supports this protocol) can respond to touch events, or to time-varying programmatic input, by speeding up, slowing down, or even reversing the progress of a view controller transition. For example, an interactive transition on a navigation controller could respond to a swipe gesture by moving a view controller onto or off of the navigation stack. To support an interactive view controller transition, you must also provide a transition animator delegate, which is a custom object that adopts the [`UIViewControllerAnimatedTransitioning`](/documentation/UIKit/UIViewControllerAnimatedTransitioning) protocol. The transition delegate and the transition animator can, if you wish, be defined within a single custom class, but the class must adopt both protocols. If you instead want to provide a fixed-duration animated view controller transition — one that doesn’t support user interaction — use a transition animator delegate on its own. Refer to [`UIViewControllerAnimatedTransitioning`](/documentation/UIKit/UIViewControllerAnimatedTransitioning). For the methods you can call to retrieve view transition context information from within your [`startInteractiveTransition(_:)`](/documentation/UIKit/UIViewControllerInteractiveTransitioning/startInteractiveTransition(_:)) method, refer to [`UIViewControllerContextTransitioning`](/documentation/UIKit/UIViewControllerContextTransitioning). ## Topics ### Starting an interactive transition [`startInteractiveTransition(_:)`](/documentation/UIKit/UIViewControllerInteractiveTransitioning/startInteractiveTransition(_:)) Called when the system needs to set up the interactive portions of a view controller transition and start the animations. [`wantsInteractiveStart`](/documentation/UIKit/UIViewControllerInteractiveTransitioning/wantsInteractiveStart) A Boolean value indicating whether the transition is interactive when it starts. ### Providing a transition’s completion characteristics [`completionCurve`](/documentation/UIKit/UIViewControllerInteractiveTransitioning/completionCurve) Called when the system needs the animation completion curve for an interactive view controller transition. [`completionSpeed`](/documentation/UIKit/UIViewControllerInteractiveTransitioning/completionSpeed) Called when the system needs the speed at which to complete an interactive transition, after the interactive portion is finished. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)