ios – 从不调用交互式代理方法

让我们想象你的根场景(“Root”)呈现导航控制器场景(“Nav”),然后从场景A推送到B到C,例如,我想象一个这样的对象模型,导航控制器只会拥有自己的动画控制器,交互控制器和手势识别器：

这是您在考虑(a)“root”呈现“nav”时的自定义转换(非交互式)时所需要的; (b)当“nav”自行解散以返回“根”时的自定义转换(交互与否).所以,我将导航控制器子类化为：

>在其视图中添加手势识别器;
>设置transitioningDelegate以在从根场景转换到导航控制器场景(并返回)时生成自定义动画：
> transitioningDelegate还将返回交互控制器(仅在手势识别器正在进行时才存在),如果您在手势的上下文之外解除,则在手势和非交互式转换期间产生交互式转换.

在Swift 3中,它看起来像：

import UIKit
import UIKit.UIGestureRecognizerSubclass

class CustomNavigationController: UINavigationController {

    public required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        configure()
    }

    override init(rootViewController: UIViewController) {
        super.init(rootViewController: rootViewController)
        configure()
    }

    private func configure() {
        transitioningDelegate = self   // for presenting the original navigation controller
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        delegate = self                // for navigation controller custom transitions

        let left = UIScreenEdgePanGestureRecognizer(target: self,action: #selector(handleSwipeFromLeft(_:)))
        left.edges = .left
        view.addGestureRecognizer(left)
    }

    fileprivate var interactionController: UIPercentDrivenInteractiveTransition?

    func handleSwipeFromLeft(_ gesture: UIScreenEdgePanGestureRecognizer) {
        let percent = gesture.translation(in: gesture.view!).x / gesture.view!.bounds.size.width

        if gesture.state == .began {
            interactionController = UIPercentDrivenInteractiveTransition()
            if viewControllers.count > 1 {
                popViewController(animated: true)
            } else {
                dismiss(animated: true)
            }
        } else if gesture.state == .changed {
            interactionController?.update(percent)
        } else if gesture.state == .ended {
            if percent > 0.5 && gesture.state != .cancelled {
                interactionController?.finish()
            } else {
                interactionController?.cancel()
            }
            interactionController = nil
        }
    }
}

// MARK: - UINavigationControllerDelegate
//
// Use this for custom transitions as you push/pop between the varIoUs child view controllers 
// of the navigation controller. If you don't need a custom animation there,you can comment this
// out.

extension CustomNavigationController: UINavigationControllerDelegate {

    func navigationController(_ navigationController: UINavigationController,animationControllerFor operation: UINavigationControllerOperation,from fromVC: UIViewController,to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {

        if operation == .push {
            return ForwardAnimator()
        } else if operation == .pop {
            return BackAnimator()
        }
        return nil
    }

    func navigationController(_ navigationController: UINavigationController,interactionControllerFor animationController: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
        return interactionController
    }

}

// MARK: - UIViewControllerTransitioningDelegate
//
// This is needed for the animation when we initially present the navigation controller. 
// If you're only looking for custom animations as you push/pop between the child view
// controllers of the navigation controller,this is not needed. This is only for the 
// custom transition of the initial `present` and `dismiss` of the navigation controller 
// itself.

extension CustomNavigationController: UIViewControllerTransitioningDelegate {

    func animationController(forPresented presented: UIViewController,presenting: UIViewController,source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return ForwardAnimator()
    }

    func animationController(fordismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return BackAnimator()
    }

    func interactionControllerForPresentation(using animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
        return interactionController
    }

    func interactionControllerFordismissal(using animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
        return interactionController
    }

    func presentationController(forPresented presented: UIViewController,presenting: UIViewController?,source: UIViewController) -> UIPresentationController? {
        return PresentationController(presentedViewController: presented,presenting: presenting)
    }

}

// When doing custom `present`/`dismiss` that overlays the entire
// screen,you generally want to remove the presenting view controller's
// view from the view hierarchy. This presentation controller
// subclass accomplishes that for us.

class PresentationController: UIPresentationController {
    override var shouldRemovePresentersView: Bool { return true }
}

// You can do whatever you want in the animation; I'm just fading

class ForwardAnimator : NSObject,UIViewControllerAnimatedTransitioning {

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

    func animateTransition(using context: UIViewControllerContextTransitioning) {
        let toView = context.viewController(forKey: .to)!.view!

        context.containerView.addSubview(toView)

        toView.alpha = 0.0

        UIView.animate(withDuration: transitionDuration(using: context),animations: {
            toView.alpha = 1.0
        },completion: { finished in
            context.completeTransition(!context.transitionWasCancelled)
        })
    }

}

class BackAnimator : NSObject,UIViewControllerAnimatedTransitioning {

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

    func animateTransition(using context: UIViewControllerContextTransitioning) {
        let toView   = context.viewController(forKey: .to)!.view!
        let fromView = context.viewController(forKey: .from)!.view!

        context.containerView.insertSubview(toView,belowSubview: fromView)

        UIView.animate(withDuration: transitionDuration(using: context),animations: {
            fromView.alpha = 0.0
        },completion: { finished in
            context.completeTransition(!context.transitionWasCancelled)
        })
    }
}

因此,我可以将故事板中我的导航控制器的基类更改为此自定义子类,现在根场景可以只显示导航控制器(没有特殊的准备(对于:))并且一切正常.