UINavigationControllerDelegate doesn't work

Question

Update to correct version, since have got the answer.

I want to do fade in/fade out animation when navigation view controller pop up /push, then I implement a BaseViewController :

class BaseViewController: UIViewController, UINavigationControllerDelegate {

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)
        self.navigationController?.delegate = self
    }


    func navigationController(navigationController: UINavigationController, animationControllerForOperation operation: UINavigationControllerOperation, fromViewController fromVC: UIViewController, toViewController toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {

        if (operation == UINavigationControllerOperation.Push) {
            return FadeInAnimator()
        }

        if (operation == UINavigationControllerOperation.Pop) {
            return FadeOutAnimator()
        }
        return nil;
    }
}

and FadeInAnimator , FadeOutAnimator :

class FadeInAnimator: NSObject, UIViewControllerAnimatedTransitioning {

    func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return 0.5
    }

    func animateTransition(transitionContext: UIViewControllerContextTransitioning) {

        let toViewController = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)
        transitionContext.containerView()?.addSubview(toViewController!.view)
        toViewController?.view.alpha = 0.0
        UIView.animateWithDuration(self.transitionDuration(transitionContext), animations: { () -> Void in
            toViewController?.view.alpha = 1.0
        }) { (finished) -> Void in
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled())
        }
    }
}

class FadeOutAnimator: NSObject, UIViewControllerAnimatedTransitioning {
    func transitionDuration(transitionContext: UIViewControllerContextTransitioning?) -> NSTimeInterval {
        return 0.5
    }

    func animateTransition(transitionContext: UIViewControllerContextTransitioning) {
        let toViewController = transitionContext.viewControllerForKey(UITransitionContextToViewControllerKey)
        let fromViewController = transitionContext.viewControllerForKey(UITransitionContextFromViewControllerKey)
        transitionContext.containerView()?.insertSubview((toViewController?.view)!, belowSubview: (fromViewController?.view)!)

        UIView.animateWithDuration(self.transitionDuration(transitionContext), animations: { () -> Void in
            fromViewController?.view.alpha = 0.0
        }) { (finished) -> Void in
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled())
    }
}

Then, I add 2 view controllers and embed navigation view controller, ViewControllerA and ViewControllerB :

class ViewControllerA: BaseViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    @IBAction func pressButton(sender: UIButton) {

        if let vc = create(ViewControllerB) {
            self.navigationController?.pushViewController(vc, animated: true)
        }
    }  
}

class ViewControllerB: BaseViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

    }
}

press button on ViewControllerA will create and jump to ViewControllerB , then press navigation bar item "back" on ViewControllerB will back to ViewControllerA .

But it doesn't work, when press button, the ViewControllerA show ViewControllerB , then show ViewControllerA again.

any suggestion? my xcode is 7.1 and run on iPad Air 2 simulator.

Answer 1

in your FadeInAnimator at animation completion block

change this

transitionContext.completeTransition(transitionContext.transitionWasCancelled())

to

transitionContext.completeTransition(!transitionContext.transitionWasCancelled())