Swift：实例化视图控制器以在当前导航堆栈中进行自定义转换

Question

简介

我正在创建一个应用程序，它的 rootViewController 中有一个 UITableView 和一个 UIPanGestureRecognizer 附加到一个小的 UIView 充当“句柄”，它可以为 UIViewController 启用自定义视图控制器转换调用“SlideOutViewController”从右侧平移。

问题

我注意到我的方法存在两个问题。但实际的自定义转换按预期工作。

1. 当 SlideOutViewController 创建时，我相信它不会附加到导航堆栈，因此它没有关联的导航栏。如果我使用navigationController 将其推送到堆栈上，我会失去交互转换。

2. 旁注：我还没有找到将句柄连接到以交互方式拖出的 SlideOutViewController 的方法。所以handle的平移和SlideOutViewControllers位置不一致。

问题

• 如何将 SlideOutViewController 添加到导航堆栈？这样当我触发UIPanGestureRecognizer 时，SlideOutViewController 会使用导航栏进行转换？

我的代码

在 rootViewController 中。

class RootViewController: UIViewController {

    ...

    let slideControllerHandle = UIView()
    var interactionController : UIPercentDrivenInteractiveTransition?

    override func viewDidLoad() {
        super.viewDidLoad()

        ... // Setting up the table view etc...

        setupPanGForSlideOutController()
    }

    private func setupPanGForSlideOutController() {
         slideControllerHandle.translatesAutoresizingMaskIntoConstraints = false
         slideControllerHandle.layer.borderColor = UIColor.black.cgColor
         slideControllerHandle.layer.borderWidth = 1
         slideControllerHandle.layer.cornerRadius = 30
         view.addSubview(slideControllerHandle)
         slideControllerHandle.frame = CGRect(x: view.frame.width - 12.5, y: view.frame.height / 2, width: 25, height: 60)
         let panGestureForCalendar = UIPanGestureRecognizer(target: self, action: #selector(handlePanGestureForSlideOutViewController(_:)))
         slideControllerHandle.addGestureRecognizer(panGestureForCalendar)
    }

    @objc private func handlePanGestureForSlideOutViewController(_ gesture: UIPanGestureRecognizer) {

         let xPosition = gesture.location(in: view).x
         let percent = 1 - (xPosition / view.frame.size.width)

         switch gesture.state {
         case .began:
             guard let slideOutController = storyboard?.instantiateViewController(withIdentifier: "CNSlideOutViewControllerID") as? SlideOutViewController else { fatalError("Sigh...") }
             interactionController = UIPercentDrivenInteractiveTransition()
        slideOutController.customTransitionDelegate.interactionController = interactionController
             self.present(slideOutController, animated: true)
         case .changed:
             slideControllerHandle.center = CGPoint(x: xPosition, y: slideControllerHandle.center.y)
             interactionController?.update(percent)
         case .ended, .cancelled:
             let velocity = gesture.velocity(in: view)
             interactionController?.completionSpeed = 0.999
             if percent > 0.5 || velocity.x < 10 {
                 UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
                     self.slideControllerHandle.center = CGPoint(x: self.view.frame.width, y: self.slideControllerHandle.center.y)
                 })
                 interactionController?.finish()
             } else {
                 UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 0.8, initialSpringVelocity: 0.5, options: .curveEaseInOut, animations: {
                     self.slideControllerHandle.center = CGPoint(x: -25, y: self.slideControllerHandle.center.y)
                 })
                 interactionController?.cancel()
             }
             interactionController = nil
         default:
             break
         }
    }

SlideOutViewController

class SlideOutViewController: UIViewController {

    var interactionController : UIPercentDrivenInteractiveTransition?
    let customTransitionDelegate = TransitionDelegate()

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        modalPresentationStyle = .custom
        transitioningDelegate = customTransitionDelegate
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .red
        navigationItem.title = "Slide Controller"
        let addButton = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(addNewData(_:)))
        navigationItem.setRightBarButton(addButton, animated: true)
    }

}

自定义转换代码。 Based on Rob's descriptive answer on this SO question

1. TransitionDelegate

   class TransitioningDelegate: NSObject, UIViewControllerTransitioningDelegate {
   
       weak var interactionController : UIPercentDrivenInteractiveTransition?
       func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
           return CNRightDragAnimationController(transitionType: .presenting)
       }
   
       func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
           return CNRightDragAnimationController(transitionType: .dismissing)
       }
   
       func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController? {
           return PresentationController(presentedViewController: presented, presenting: presenting)
       }
   
       func interactionControllerForPresentation(using animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
           return interactionController
       }    
   
       func interactionControllerForDismissal(using animator: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {
           return interactionController
       }
   }
   

2. DragAnimatedTransitioning

   class CNRightDragAnimationController: NSObject, UIViewControllerAnimatedTransitioning {
   
       enum TransitionType {
           case presenting
           case dismissing
       }
   
       let transitionType: TransitionType
   
       init(transitionType: TransitionType) {
           self.transitionType = transitionType
           super.init()
       }
   
       func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
           let inView   = transitionContext.containerView
           let toView   = transitionContext.view(forKey: .to)!
           let fromView = transitionContext.view(forKey: .from)!
   
           var frame = inView.bounds
   
           switch transitionType {
           case .presenting:
               frame.origin.x = frame.size.width
               toView.frame = frame
   
               inView.addSubview(toView)
               UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
                   toView.frame = inView.bounds
               }, completion: { finished in
                   transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
               })
           case .dismissing:
               toView.frame = frame
               inView.insertSubview(toView, belowSubview: fromView)
   
               UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
                   frame.origin.x = frame.size.width
                   fromView.frame = frame
               }, completion: { finished in
                   transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
               })
           }
       }
   
       func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
           return 0.5
       }
   }
   

3. 演示控制器

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

感谢您阅读我的问题。

Answer 1

您从中获取的动画代码用于自定义“当前”（例如模态）过渡。但是，如果您在使用导航控制器时在推/弹出时想要自定义导航，则为您的UINavigationController 指定一个委托，然后在navigationController(_:animationControllerFor:from:to:) 中返回适当的转换委托。并且还实现navigationController(_:interactionControllerFor:) 并在那里返回您的交互控制器。

---

例如我会做类似的事情：

class FirstViewController: UIViewController {

    let navigationDelegate = CustomNavigationDelegate()

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationController?.delegate = navigationDelegate
        navigationDelegate.addPushInteractionController(to: view)
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        navigationDelegate.pushDestination = { [weak self] in
            self?.storyboard?.instantiateViewController(withIdentifier: "Second")
        }
    }
}

地点：

class CustomNavigationDelegate: NSObject, UINavigationControllerDelegate {

    var interactionController: UIPercentDrivenInteractiveTransition?
    var current: UIViewController?
    var pushDestination: (() -> UIViewController?)?

    func navigationController(_ navigationController: UINavigationController,
                              animationControllerFor operation: UINavigationController.Operation,
                              from fromVC: UIViewController,
                              to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return CustomNavigationAnimator(transitionType: operation)
    }

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

    func navigationController(_ navigationController: UINavigationController, didShow viewController: UIViewController, animated: Bool) {
        current = viewController
    }
}

// MARK: - Push

extension CustomNavigationDelegate {
    func addPushInteractionController(to view: UIView) {
        let swipe = UIScreenEdgePanGestureRecognizer(target: self, action: #selector(handlePushGesture(_:)))
        swipe.edges = [.right]
        view.addGestureRecognizer(swipe)
    }

    @objc private func handlePushGesture(_ gesture: UIScreenEdgePanGestureRecognizer) {
        guard let pushDestination = pushDestination else { return }

        let position = gesture.translation(in: gesture.view)
        let percentComplete = min(-position.x / gesture.view!.bounds.width, 1.0)

        switch gesture.state {
        case .began:
            interactionController = UIPercentDrivenInteractiveTransition()
            guard let controller = pushDestination() else { fatalError("No push destination") }
            current?.navigationController?.pushViewController(controller, animated: true)

        case .changed:
            interactionController?.update(percentComplete)

        case .ended, .cancelled:
            let speed = gesture.velocity(in: gesture.view)
            if speed.x < 0 || (speed.x == 0 && percentComplete > 0.5) {
                interactionController?.finish()
            } else {
                interactionController?.cancel()
            }
            interactionController = nil

        default:
            break
        }
    }
}

// MARK: - Pop

extension CustomNavigationDelegate {
    func addPopInteractionController(to view: UIView) {
        let swipe = UIScreenEdgePanGestureRecognizer(target: self, action: #selector(handlePopGesture(_:)))
        swipe.edges = [.left]
        view.addGestureRecognizer(swipe)
    }

    @objc private func handlePopGesture(_ gesture: UIScreenEdgePanGestureRecognizer) {
        let position = gesture.translation(in: gesture.view)
        let percentComplete = min(position.x / gesture.view!.bounds.width, 1)

        switch gesture.state {
        case .began:
            interactionController = UIPercentDrivenInteractiveTransition()
            current?.navigationController?.popViewController(animated: true)

        case .changed:
            interactionController?.update(percentComplete)

        case .ended, .cancelled:
            let speed = gesture.velocity(in: gesture.view)
            if speed.x > 0 || (speed.x == 0 && percentComplete > 0.5) {
                interactionController?.finish()
            } else {
                interactionController?.cancel()
            }
            interactionController = nil


        default:
            break
        }
    }
}

和

class CustomNavigationAnimator: NSObject, UIViewControllerAnimatedTransitioning {

    let transitionType: UINavigationController.Operation

    init(transitionType: UINavigationController.Operation) {
        self.transitionType = transitionType
        super.init()
    }

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        let inView   = transitionContext.containerView
        let toView   = transitionContext.view(forKey: .to)!
        let fromView = transitionContext.view(forKey: .from)!

        var frame = inView.bounds

        switch transitionType {
        case .push:
            frame.origin.x = frame.size.width
            toView.frame = frame

            inView.addSubview(toView)
            UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
                toView.frame = inView.bounds
            }, completion: { finished in
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
            })

        case .pop:
            toView.frame = frame
            inView.insertSubview(toView, belowSubview: fromView)

            UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
                frame.origin.x = frame.size.width
                fromView.frame = frame
            }, completion: { finished in
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
            })

        case .none:
            break
        }
    }

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

然后，如果第二个视图控制器想要自定义交互式弹出以及滑动到第三个视图控制器的能力：

class SecondViewController: UIViewController {

    var navigationDelegate: CustomNavigationDelegate { return navigationController!.delegate as! CustomNavigationDelegate }

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationDelegate.addPushInteractionController(to: view)
        navigationDelegate.addPopInteractionController(to: view)
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        navigationDelegate.pushDestination = { [weak self] in
            self?.storyboard?.instantiateViewController(withIdentifier: "Third")
        }
    }

}

但是如果最后一个视图控制器不能推送到任何东西，而只能弹出：

class ThirdViewController: UIViewController {

    var navigationDelegate: CustomNavigationDelegate { return navigationController!.delegate as! CustomNavigationDelegate }

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationDelegate.addPopInteractionController(to: view)
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        navigationDelegate.pushDestination = nil
    }

}