Question

我将UINavigationController子类化，并创建了一个处理推送和弹出过渡的非交互式动画对象。要完成此操作，如何添加UIScreenEdgePanGestureRecognizer来处理下面的自定义流行动画？我有点困惑，从这里去哪里，所以任何帮助都会很棒，谢谢！

class CustomNavigationController: UINavigationController {

    override func viewDidLoad() {
        super.viewDidLoad()

        delegate = self
        isNavigationBarHidden = true

    }

}

extension CustomNavigationController: UINavigationControllerDelegate {

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

        switch operation {

        case .push:
            return CustomPushAnimator()

        case .pop:
            return CustomPopAnimator()

        default:
            return nil

        }

    }

    // the interactive animator controller
    func navigationController(_ navigationController: UINavigationController, interactionControllerFor animationController: UIViewControllerAnimatedTransitioning) -> UIViewControllerInteractiveTransitioning? {

        switch animationController {

        case is CustomPopAnimator:
            return CustomInteractiveController()

        default:
            return nil

    }

}

// the noninteractive push animator
class CustomPushAnimator: NSObject, UIViewControllerAnimatedTransitioning {

    // push transition duration
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {

        return 0.2

    }

    // push transition animation
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {

        let viewWidth = UIScreen.main.bounds.width
        let viewHeight = UIScreen.main.bounds.height
        let containerView = transitionContext.containerView
        let toViewController = transitionContext.viewController(forKey: .to)

        containerView.addSubview((toViewController?.view)!)
        toViewController?.view.frame = CGRect(x: viewWidth, y: 0, width: viewWidth, height: viewHeight)

        UIView.animate(withDuration: transitionDuration(using: transitionContext), delay: 0, options: UIViewAnimationOptions.curveEaseInOut, animations: {
            toViewController?.view.frame = CGRect(x: 0, y: 0, width: viewWidth, height: viewHeight)
        }, completion: { finished in
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        })

    }

}

// the noninteractive pop animator
class CustomPopAnimator: NSObject, UIViewControllerAnimatedTransitioning {

    // pop transition duration
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {

        return 0.2

    }

    // pop transition animation
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {

        let viewWidth = UIScreen.main.bounds.width
        let viewHeight = UIScreen.main.bounds.height
        let containerView = transitionContext.containerView
        let fromViewController = transitionContext.viewController(forKey: .from)
        let toViewController = transitionContext.viewController(forKey: .to)

        containerView.insertSubview((toViewController?.view)!, belowSubview: (fromViewController?.view)!)

        UIView.animate(withDuration: transitionDuration(using: transitionContext), delay: 0, options: UIViewAnimationOptions.curveEaseInOut, animations: {
            fromViewController?.view.frame = CGRect(x: viewWidth, y: 0, width: viewWidth, height: viewHeight)
        }, completion: { finished in
            fromViewController?.view.removeFromSuperview()
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        })

    }

}

class CustomInteractiveController: NSObject, UIViewControllerInteractiveTransitioning {

    func startInteractiveTransition(_ transitionContext: UIViewControllerContextTransitioning) {

        // I think the edge screen pan gesture goes here? Again, any advice is greatly appreciated!

    }

}

Answer 1

通常，编写交互式自定义过渡动画的过程是：

在转换开始之前，您必须已经让视图控制器负责代表的过渡。
您将拥有一个跟踪交互式手势的手势识别器。当手势识别器识别时，它会触发向新视图控制器的转换。
随着转换的开始，代表将被要求提供动画控制器。您将返回一个UIViewControllerAnimatedTransitioning对象。
还会要求代表提供交互控制器。您将返回UIViewControllerInteractiveTransitioning对象（或nil以防止转换为交互）。该对象实现startInteractiveTransition(_:)。
手势识别器继续在转换上下文中不断调用updateInteractiveTransition(_:)，以及管理动画的帧。
手势迟早会结束。此时，我们必须决定是否声明过渡完成或取消。一种典型的方法是，如果用户执行完整手势的一半以上，则构成完成;否则，它构成取消。我们相应地完成动画。
动画现已完成，并调用其完成功能。我们必须调用转换上下文的finishInteractiveTransition或cancelInteractiveTransition，然后使用参数调用其completeTransition(_:)，说明转换是完成还是取消。
我们调用了animationEnded，我们会进行清理。

过去，您可以使用UIPercentDrivenInteractiveTransition对象来帮助您，但我现在总是使用UIViewPropertyAnimator来制作自定义过渡动画（iOS 10及更高版本）;你必须从重写整个代码开始这样做。我通常保留三个实例属性：UIViewPropertyAnimator，转换上下文（因为手势识别器需要引用），以及Bool标志，说明这是否是交互式动画（因为相同的代码可以重用于交互式和非交互式动画动画）。

如何添加屏幕边缘平移手势识别器来处理此流行动画？

1 个答案: