ios - 如何在自定义 navigationController 代码中定位特定的 viewController？

Question

我有这个要实现的自定义 navigationController 动画，但我希望仅当特定的 viewController 在堆栈上时才实现代码。这是代码:

class ARNImageTransitionNavigationController: UINavigationController, UINavigationControllerDelegate {

    weak var interactiveAnimator : ARNTransitionAnimator?
    var currentOperation : UINavigationControllerOperation = .None

    override func viewDidLoad() {
        super.viewDidLoad()

        self.interactivePopGestureRecognizer?.enabled = false
        self.delegate = self
    }

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

        if let _interactiveAnimator = self.interactiveAnimator {
            return _interactiveAnimator
        }

        if operation == .Push {
            return ARNImageZoomTransition.createAnimator(.Push, fromVC: fromVC, toVC: toVC)
        } else if operation == .Pop {
            return ARNImageZoomTransition.createAnimator(.Pop, fromVC: fromVC, toVC: toVC)
        }

        return nil
    }

    func navigationController(navigationController: UINavigationController, interactionControllerForAnimationController animationController: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
        if let _interactiveAnimator = self.interactiveAnimator {
            if  self.currentOperation == .Pop {
                return _interactiveAnimator
            }
        }
        return nil
    }
}

现在我应该向此代码添加什么，以确保它实现其所有方法，但仅当特定的 viewController 位于堆栈上时？

Answer 1

如果您已经为有问题的 View Controller 提供了单独的 swift 类，那么您可以检查它们的文件类名。假设你在插入时想要这个动画，例如ProfilePageViewController导航堆栈，然后使用 if operation == .Push && toVC.isKindOfClass(ProfilePageViewController) 。我在您提供的代码示例中添加了剩余的代码。

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

    if let _interactiveAnimator = self.interactiveAnimator {
        return _interactiveAnimator
    }

    if operation == .Push && toVC.isKindOfClass(swiftNameofVCClassFile) {
        return ARNImageZoomTransition.createAnimator(.Push, fromVC: fromVC, toVC: toVC)
    } else if operation == .Pop && fromVC.isKindOfClass(swiftNameofVCClassFile) {
        return ARNImageZoomTransition.createAnimator(.Pop, fromVC: fromVC, toVC: toVC)
    }

    return nil
}