從不調用交互式代理方法

Question

我想在ViewController（1）和NavigationViewController（2）之間進行交互式轉換。

NavigationController由一個按鈕調用，因此在呈現時沒有交互式轉換。 它可以通過按鈕或UIPanGestureRecognizer來解除，因此它可以被交互或不被解雇。

我有一個名為TransitionManager的對象，用於轉換，UIPercentDrivenInteractiveTransition的子類。

下面的代碼的問題是從不調用兩個委托方法interactionControllerFor...

此外，當我按下按鈕或swip（UIPanGestureRecognizer）時，模態segue的基本動畫完成。 所以兩個委托方法animationControllerFor...也不起作用。

有任何想法嗎 ？ 謝謝

ViewController.swift

let transitionManager = TransitionManager()

override func viewDidLoad() {
    super.viewDidLoad()

    self.transitioningDelegate = transitionManager
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

        let dest = segue.destinationViewController as UIViewController
        dest.transitioningDelegate = transitionManager
        dest.modalPresentationStyle = .Custom
}

TransitionManager.swift

class TransitionPushManager: UIPercentDrivenInteractiveTransition,
 UINavigationControllerDelegate, UIViewControllerTransitioningDelegate {


@IBOutlet var navigationController: UINavigationController!

var animation : Animator! // Implement UIViewControllerAnimatedTransitioning protocol


override func awakeFromNib() {
    var panGesture = UIPanGestureRecognizer(target: self, action: "gestureHandler:")
    navigationController.view.addGestureRecognizer(panGesture)

    animation = Animator()
}

func gestureHandler(pan : UIPanGestureRecognizer) {

    switch pan.state {

    case .Began :

        interactive = true

            navigationController.presentingViewController?.dismissViewControllerAnimated(true, completion:nil)


    case .Changed :

        ...            

    default :

        ...

        interactive = false

    }

}


func animationControllerForPresentedController(presented: UIViewController, presentingController presenting: UIViewController, sourceController source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    return animation
}

func animationControllerForDismissedController(dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    return animation
}

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

func interactionControllerForDismissal(animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
    return self.interactive ? self : nil
}

Main.storyboard

• ViewController上的按鈕觸發了一個模態segue來呈現NavigationController

• NavigationController的委托出口鏈接到TransitionManager類的對象

• NavigationController在屬性“navigationController”的TransitionManager類中引用

Answer 1

我認為關鍵問題是你在viewDidLoad配置transitionDelegate 。 在這個過程中，這通常為時已晚。 您應該在init導航控制器時執行此操作。

讓我們想象你的根場景（“Root”），它呈現導航控制器場景（“Nav”），然后從場景A推送到B到C，例如，我想象一個像這樣的對象模型，導航控制器只會擁有自己的動畫控制器，交互控制器和手勢識別器：

這是您在考慮（a）“root”呈現“nav”時的自定義轉換（非交互式）時所需要的; （b）當“nav”自行解散以返回“根”時的自定義轉換（交互與否）。 所以，我將導航控制器子類化為：

• 在其視圖中添加手勢識別器;

• 設置transitioningDelegate以在從根場景轉換到導航控制器場景（並返回）時生成自定義動畫：

• transitioningDelegate還將返回交互控制器（僅在手勢識別器正在進行時才存在），如果您在手勢的上下文之外解除，則在手勢和非交互式轉換期間產生交互式轉換。

在Swift 3中，它看起來像：

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)
        })
    }
}

所以，我可以將故事板中導航控制器的基類更改為此自定義子類，現在根場景可以只顯示導航控制器（沒有特殊的prepare(for:) ），一切正常。