Question

这是我的自定义搜索代码

class FlipFromRightSegue: UIStoryboardSegue {
override func perform() {
    let source:UIViewController = self.sourceViewController as UIViewController
    let destination:UIViewController = self.destinationViewController as UIViewController

    UIView.transitionWithView(source.view, duration: 1.0, options: .CurveEaseInOut | .TransitionFlipFromRight, animations: { () -> Void in
        source.view.addSubview(destination.view)
    }) { (finished) -> Void in
        destination.view.removeFromSuperview()
        source.presentViewController(destination, animated: false, completion: nil)
    }
}
}

我认为这样可行，但实际上只有在已执行segue时视图才会更改。当“翻转”位于中间时，我该怎么做才能使视图发生变化？

提前致谢。

Answer 1

从iOS 7开始，我们通常不使用自定义segue为转换设置动画。我们要么使用标准模态演示文稿，指定modalTransitionStyle（即我们可以为模态过渡选择的几个动画的固定列表），要么实现自定义动画过渡。这两个描述如下：

如果您只是展示另一个视图控制器的视图，将动画更改为翻转的简单解决方案是在目标视图控制器中设置modalTransitionStyle。您可以在segue的属性下完全在Interface Builder中完成此操作。

如果你想以编程方式进行，在目标控制器中你可以在Swift 3中执行以下操作：
```
override func viewDidLoad() {
    super.viewDidLoad()

    modalTransitionStyle = .flipHorizontal   // use `.FlipHorizontal` in Swift 2
}
```
然后，当您拨打show / showViewController或present / presentViewController时，您的演示文稿将以水平翻转方式执行。并且，当您关闭视图控制器时，动画会自动反转。

如果您需要更多控制，在iOS 7及更高版本中，您将使用自定义动画过渡，您可以在其中指定modalPresentationStyle .custom。例如，在Swift 3中：

class SecondViewController: UIViewController {

    let customTransitionDelegate = TransitioningDelegate()

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

        modalPresentationStyle = .custom   // use `.Custom` in Swift 2
        transitioningDelegate = customTransitionDelegate
    }

    ...
}

指定将实例化动画控制器的UIViewControllerTransitioningDelegate。例如，在Swift 3中：

class TransitioningDelegate: NSObject, UIViewControllerTransitioningDelegate {
    func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return AnimationController(transitionType: .presenting)
    }

    func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return AnimationController(transitionType: .dismissing)
    }
}

动画控制器只是.transitionFlipFromRight是一个演示文稿，或.transitionFlipFromLeft如果在Swift 3中解雇：

class AnimationController: NSObject, UIViewControllerAnimatedTransitioning {

    enum TransitionType {
        case presenting
        case dismissing
    }

    var animationTransitionOptions: UIViewAnimationOptions

    init(transitionType: TransitionType) {
        switch transitionType {
        case .presenting:
            animationTransitionOptions = .transitionFlipFromRight
        case .dismissing:
            animationTransitionOptions = .transitionFlipFromLeft
        }

        super.init()
    }

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

        UIView.transition(from: fromView!, to: toView!, duration: transitionDuration(using: transitionContext), options: animationTransitionOptions.union(.curveEaseInOut)) { finished in
            transitionContext.completeTransition(true)
        }
    }

    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 1.0
    }
}

有关iOS 7中引入的自定义转换的详细信息，请参阅WWDC 2013视频Custom Transitions Using View Controllers。

如果应该承认上述AnimationController实际上是过度简化，因为我们正在使用transform(from:to:...)。这会导致动画无法取消（如果您正在使用交互式转换）。它也删除了“从”视图本身，从iOS 8开始，现在它实际上是演示控制器的工作。

所以，你真的想用UIView.animate API做翻转动画。我很抱歉，因为以下内容涉及在关键帧动画中使用一些不直观的CATransform3D，但它会产生一个翻转动画，然后可以进行可取消的交互式过渡。

所以，在Swift 3中：

class AnimationController: 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

        func flipTransform(angle: CGFloat, offset: CGFloat = 0) -> CATransform3D {
            var transform = CATransform3DMakeTranslation(offset, 0, 0)
            transform.m34 = -1.0 / 1600
            transform = CATransform3DRotate(transform, angle, 0, 1, 0)
            return transform
        }

        toView.frame = inView.bounds
        toView.alpha = 0

        let transformFromStart:  CATransform3D
        let transformFromEnd:    CATransform3D
        let transformFromMiddle: CATransform3D
        let transformToStart:    CATransform3D
        let transformToMiddle:   CATransform3D
        let transformToEnd:      CATransform3D

        switch transitionType {
        case .presenting:
            transformFromStart  = flipTransform(angle: 0,        offset: inView.bounds.size.width / 2)
            transformFromEnd    = flipTransform(angle: -.pi,     offset: inView.bounds.size.width / 2)
            transformFromMiddle = flipTransform(angle: -.pi / 2)
            transformToStart    = flipTransform(angle: .pi,      offset: -inView.bounds.size.width / 2)
            transformToMiddle   = flipTransform(angle: .pi / 2)
            transformToEnd      = flipTransform(angle: 0,        offset: -inView.bounds.size.width / 2)

            toView.layer.anchorPoint = CGPoint(x: 0, y: 0.5)
            fromView.layer.anchorPoint = CGPoint(x: 1, y: 0.5)

        case .dismissing:
            transformFromStart  = flipTransform(angle: 0,        offset: -inView.bounds.size.width / 2)
            transformFromEnd    = flipTransform(angle: .pi,      offset: -inView.bounds.size.width / 2)
            transformFromMiddle = flipTransform(angle: .pi / 2)
            transformToStart    = flipTransform(angle: -.pi,     offset: inView.bounds.size.width / 2)
            transformToMiddle   = flipTransform(angle: -.pi / 2)
            transformToEnd      = flipTransform(angle: 0,        offset: inView.bounds.size.width / 2)

            toView.layer.anchorPoint = CGPoint(x: 1, y: 0.5)
            fromView.layer.anchorPoint = CGPoint(x: 0, y: 0.5)
        }

        toView.layer.transform = transformToStart
        fromView.layer.transform = transformFromStart
        inView.addSubview(toView)

        UIView.animateKeyframes(withDuration: self.transitionDuration(using: transitionContext), delay: 0, options: [], animations: {
            UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 0.0) {
                toView.alpha = 0
                fromView.alpha = 1
            }
            UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 0.5) {
                toView.layer.transform = transformToMiddle
                fromView.layer.transform = transformFromMiddle
            }
            UIView.addKeyframe(withRelativeStartTime: 0.5, relativeDuration: 0.0) {
                toView.alpha = 1
                fromView.alpha = 0
            }
            UIView.addKeyframe(withRelativeStartTime: 0.5, relativeDuration: 0.5) {
                toView.layer.transform = transformToEnd
                fromView.layer.transform = transformFromEnd
            }
        }, completion: { finished in
            toView.layer.transform = CATransform3DIdentity
            fromView.layer.transform = CATransform3DIdentity
            toView.layer.anchorPoint = CGPoint(x: 0.5, y: 0.5)
            fromView.layer.anchorPoint = CGPoint(x: 0.5, y: 0.5)

            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        })
    }

    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 1.0
    }
}

仅供参考，iOS 8使用演示控制器扩展了自定义转换模型。有关详细信息，请参阅WWDC 2014视频A Look Inside Presentation Controllers。

无论如何，如果在转换结束时，“from”视图不再可见，您将指示您的演示控制器将其从视图层次结构中删除，例如：

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

显然，您必须通知此演示控制器的TransitioningDelegate：

class TransitioningDelegate: NSObject, UIViewControllerTransitioningDelegate {

    ...

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

此答案已针对Swift 3进行了更新。如果您想查看Swift 2实施，请参阅previous revision of this answer。

Swift中的自定义Flip Segue

1 个答案: