How to apply custom transition animation in UINavigationControllerDelegate to specific push and pop events?

Question

I have a custom animation transition for push and pop events in a UINavigationController stack and I want to apply that custom animation only to specific push events--for example, when pushing RandomViewController44() or popping RandomViewController27()--not every push and pop in the stack. Is that done in the UINavigationControllerDelegate, in the animator object, or at the point of push/pop?

The delegate

extension BaseViewController: UINavigationControllerDelegate {

    func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationControllerOperation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        switch operation {
        case .push:
            return InAnimator()
        case .pop:
            return OutAnimator()
        default:
            return nil
        }
    }

}

The animator object

class InAnimator: NSObject, UIViewControllerAnimatedTransitioning {

    let animationDuration = 0.5

    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return animationDuration
    }

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {

        let screenHeight = UIScreen.main.bounds.height
        let screenWidth = UIScreen.main.bounds.width
        let containerView = transitionContext.containerView
        let toViewController = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to)

        containerView.addSubview(toViewController!.view)

        toViewController!.view.frame = CGRect(x: screenWidth * -1, y: 0, width: screenWidth, height: screenHeight)

        UIView.animate(withDuration: animationDuration, animations: {
            toViewController!.view.frame = CGRect(x: 0, y: 0, width: screenWidth, height: screenHeight)
        }, completion: { finished in
            let cancelled = transitionContext.transitionWasCancelled
            transitionContext.completeTransition(!cancelled)
        })

    }

}

The call to push

func pushVC() {
    navigationController?.pushViewController(randomViewController44(), animated: true)
}

Hiren Hiren · Accepted Answer · 2017-08-28T05:18:03

You Can Check the fromView and ToView controller in below delegate method for perform action

extension BaseViewController: UINavigationControllerDelegate {

    func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationControllerOperation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        switch operation {
        case .push:
            if toVc is RandomViewController44{
               return InAnimator()
            }
            return nil
        case .pop:
            if RandomViewController27 is fromVC{
              return OutAnimator()
            }
            return nil
        default:
            return nil
        }
    }
}

You need to check from and toView controller when this method called as set condition as per your requirement

How to apply custom transition animation in UINavigationControllerDelegate to specific push and pop events?

1 Answers