Swift基础之自定义PUSH和POP跳转动画

之前用OC代码写过PUSH和POP的转场动画，闲来无事，将其转换成Swift语言，希望对大家有帮助，转载请注明。。。。
如何实现PUSH和POP的转场动画？
首先，创建一个NSObject的类，分别用来实现PUSH和POP的动画效果
创建PUSH文件，实现扇形效果，代码如下：
需要注意的是，代理的实现方法要完整

var transitionContextT:UIViewControllerContextTransitioning?
    
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.8
    }
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        
        self.transitionContextT = transitionContext
        
        let fromVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from)
        let toVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to)
        //不添加的话，屏幕什么都没有
        let containerView = transitionContext.containerView
        containerView.addSubview((fromVC?.view)!)
        containerView.addSubview((toVC?.view)!)
        
        let originRect:CGRect = CGRect.init(x: 0, y: 0, width: 50, height: 50)
        let maskStartPath = UIBezierPath.init(ovalIn: originRect)
        //OC中CGRectInset(originRect, -2000, -2000)的Swift用法:originRect.insetBy(dx: -2000, dy: -2000)
        let maskEndPath = UIBezierPath.init(ovalIn: originRect.insetBy(dx: -2000, dy: -2000))
        
        //创建一个CAShapeLayer来负责展示圆形遮盖
        let maskLayer = CAShapeLayer.init()
        //将他的path指定为最终的path，来避免在动画完成后回弹
        maskLayer.path = maskEndPath.cgPath
        
        toVC?.view.layer.mask = maskLayer
        
        let maskAnimation = CABasicAnimation.init(keyPath: "path")
        maskAnimation.fromValue = maskStartPath.cgPath
        maskAnimation.toValue = maskEndPath.cgPath
        maskAnimation.duration = self.transitionDuration(using: transitionContext)
        maskAnimation.timingFunction = CAMediaTimingFunction.init(name: kCAMediaTimingFunctionEaseInEaseOut)
        maskAnimation.fillMode = kCAFillModeForwards
        maskAnimation.isRemovedOnCompletion = false
        maskAnimation.delegate = self
        maskLayer.add(maskAnimation, forKey: "path")
        
    }
    //MARK:----- CAAnimationDelegate
    func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
        self.transitionContextT?.completeTransition(!(self.transitionContextT?.transitionWasCancelled)!)
        //去除mask
        self.transitionContextT?.viewController(forKey: UITransitionContextViewControllerKey.from)?.view.layer.mask = nil;
        self.transitionContextT?.viewController(forKey: UITransitionContextViewControllerKey.to)?.view.layer.mask = nil;
    }
然后，同理创建POP文件，实现弹跳的效果，代码如下：
var transitionContext:UIViewControllerContextTransitioning?
    
    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.8
    }
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        
        self.transitionContext = transitionContext
        
        let fromVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.from)
        let toVC = transitionContext.viewController(forKey: UITransitionContextViewControllerKey.to)
        //不添加的话，屏幕什么都没有
        let containerView = transitionContext.containerView
        containerView.addSubview((fromVC?.view)!)
        containerView.addSubview((toVC?.view)!)
        
        let durationN = self.transitionDuration(using: transitionContext)
        let screenBounds:CGRect = UIScreen.main.bounds
        let finalFrame:CGRect = transitionContext.finalFrame(for: toVC!)
        //OC中CGRectOffset(finalFrame, 0, -screenBounds.size.height)的Swift的用法：finalFrame.offsetBy(dx: 0, dy: -screenBounds.size.height)
        toVC?.view.frame = finalFrame.offsetBy(dx: 0, dy: -screenBounds.size.height)

        //添加动画，有弹跳的效果,参数：usingSpringWithDamping的范围为0.0f到1.0f，数值越小「弹簧」的振动效果越明显，当设置为1.0时，就不弹跳
        //toVC?.view.frame = finalFrame
        //transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        UIView.animate(withDuration: durationN, delay: 0.0, usingSpringWithDamping: 0.6, initialSpringVelocity: 0.0, options: UIViewAnimationOptions.curveLinear, animations: {() -> Void in
            //print("11111111")
            toVC?.view.frame = finalFrame
        }, completion: ({(Bool) -> Void in
            //print("22222222")
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        }))
    }

最后在需要使用跳转动画的地方添加self.navigationController?.delegate = self代理方法，并实现，代码如下：
//MARK:-----UINavigationControllerDelegate
    func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationControllerOperation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        if operation==UINavigationControllerOperation.push {
            return BHPopAnimation()
        }
        else if operation==UINavigationControllerOperation.pop{
            return BHPushAnimation()
        }
        return nil
    }

最后附上源代码，如果有问题请留言：https://github.com/hbblzjy/SwiftPushAndPopDemo