Removing Animation From UINavigationController Pushed Unwind? - swift

Question

I have a simple push segue from one view controller to another. I want both segues (original and unwind to be unanimated).
In the attached playground, specifying false for the segue does, indeed remove the PUSH animation, but not the UNWIND animation.
Is there a way to remove the implicit animation in the UNWIND segue?
import UIKit
import PlaygroundSupport
class SourceViewController : UIViewController {
#objc func goDestination(_: Any) {
navigationController?.pushViewController(DestinationViewController(), animated: false)
}
override func loadView() {
view = UIView()
navigationItem.title = "SOURCE"
navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(goDestination(_:)))
}
}
class DestinationViewController : UIViewController {
override func loadView() {
view = UIView()
view.backgroundColor = .yellow
navigationItem.title = "DESTINATION"
}
}
PlaygroundPage.current.liveView = UINavigationController(rootViewController: SourceViewController())

Answer 1

Those animations are fully customizable from the UINavigationControllerDelegate, check out the first "Supporting Custom Transition Animations" method
https://developer.apple.com/documentation/uikit/uinavigationcontrollerdelegate
Some details here https://www.youtube.com/watch?v=jWckfDNUJVY
at 23 minutes.

Answer 2

I'm greenchecking #glotcha's answer. It led me to this Medium post, which led me to this solution (I really wanted a fade transition):
import UIKit
import PlaygroundSupport
class TransitioningAnimatorInOut: NSObject, UIViewControllerAnimatedTransitioning {
var presenting: Bool = false
func transitionDuration(using: UIViewControllerContextTransitioning?) -> TimeInterval { 0.75 }
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
guard let fromView = transitionContext.view(forKey: .from),
let toView = transitionContext.view(forKey: .to) else { return }
let container = transitionContext.containerView
if presenting {
container.addSubview(toView)
toView.alpha = 0.0
} else {
container.insertSubview(toView, belowSubview: fromView)
}
UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
if self.presenting {
toView.alpha = 1.0
} else {
fromView.alpha = 0.0
}
}) { _ in
let success = !transitionContext.transitionWasCancelled
if !success {
toView.removeFromSuperview()
}
transitionContext.completeTransition(success)
}
}
init(presenting inPresenting: Bool) { presenting = inPresenting }
}
extension UINavigationController: UINavigationControllerDelegate {
public func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationController.Operation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
if operation == .push {
return TransitioningAnimatorInOut(presenting: true)
} else {
return TransitioningAnimatorInOut(presenting: false)
}
}
}
class SourceViewController : UIViewController {
#objc func goDestination(_: Any) {
navigationController?.pushViewController(DestinationViewController(), animated: true)
}
override func loadView() {
view = UIView()
view?.backgroundColor = .yellow
navigationItem.title = "SOURCE"
navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(goDestination(_:)))
}
}
class DestinationViewController : UIViewController {
override func loadView() {
view = UIView()
view?.backgroundColor = .red
navigationItem.title = "DESTINATION"
}
}
PlaygroundPage.current.liveView = UINavigationController(rootViewController: SourceViewController())