Swift中的自定义Flip Segue

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)
    }
}
}

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,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：

>如果您只是呈现另一个视图控制器的视图,则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.

如果您想以编程方式执行此操作,则可以在目标控制器中在Swift 3中执行以下操作：

override func viewDidLoad() {
    super.viewDidLoad()

    modalTransitionStyle = .flipHorizontal   // use `.FlipHorizontal` in Swift 2
}

然后,当您调用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.custom的modalPresentationStyle.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
    }

    ...
}

这指定了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)
    }
}

动画控制器只是做.transitionFlipFromright是一个演示文稿,或者.transitionFlipFromLeft如果在Swift 3中被解雇：

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中引入的自定义过渡的更多信息,请参阅WWDC 2013视频Custom Transitions Using View Controllers.
>如果应该承认上面的AnimationController实际上是一个过度简化,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过渡).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转换.

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)
            transform.m34 = -1.0 / 1600
            transform = CATransform3DRotate(transform,angle,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通过演示控制器扩展了自定义转换模型.有关更多信息,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,你必须通知你的TransitioningDelegate这个演示控制器：

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实现,请参阅previous revision of this answer.