史上最简单的自定义转场

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1.当我们在点击进行页面跳转的时候，可能觉得系统的动画和跳转的页面太过单调。这时候就需要我们自定义转场动画了。

1.1定义一个想要跳转的控制器

let presentedVC = UIViewController()

1.2为获得的控制器添加代理，并设置类扩展遵循协议

presentedVC.transitioningDelegate = self

1.3设置转场动画的样式

presentedVC.modalPresentationStyle = UIModalPresentationStyle.custom

1.4进行页面跳转

self.present(presentedVC, animated: true, completion: nil)

2.既然遵循了transitioningDelegate就要实现代理方法

extension HomeTableViewController : UIViewControllerTransitioningDelegate

{     2.1返回控制器跳转的UIPresentationController对象

func presentationController(forPresented presented: UIViewController, presenting:       UIViewController?, source: UIViewController) -> UIPresentationController?

{

return HYXPresentationController(presentedViewController: presented, presenting: presenting)

}

2.2返回控制控制器弹出动画的执行者，也就是遵守UIViewControllerAnimatedTransitioning这个协议

func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning?

{

return self

}

2.3返回控制控制器消失动画的执行者，也就是遵守UIViewControllerAnimatedTransitioning这个协议

func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning?

{

return self

   }

}

3.自定义UIPresentationController

class HYXPresentationController: UIPresentationController {

3.1自定义UIPresentationController需要重写父类的init方法

override init(presentedViewController: UIViewController, presenting presentingViewController: UIViewController?) {

super.init(presentedViewController: presentedViewController, presenting: presentingViewController)

}

3.2在containerView即将布局子视图的时候，更改即将推出的视图的属性

override func containerViewWillLayoutSubviews()

{

presentedView?.frame = CGRect(x: 100, y: 45, width: 200, height: 200)

}

}

4.实现UIViewControllerAnimatedTransitioning协议里面的方法

extension HomeTableViewController : UIViewControllerAnimatedTransitioning

{

4.1设置自定义动画执行时间

func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval

{

return 1.0

}

4.2设置自定义动画

func animateTransition(using transitionContext: UIViewControllerContextTransitioning)

{

 4.2.1通过transitionContext取出相应的即将弹出来的控制器的view

guard let viewT = transitionContext.view(forKey: UITransitionContextViewKey.to) else {

return

}

4.2.2将viwe添加在containerView里面

transitionContext.containerView.addSubview(viewT)

 4.2.3设置view的执行动画

viewT.transform = CGAffineTransform.init(scaleX: 1.0, y: 0.0)

viewT.layer.anchorPoint = CGPoint(x: 0.5, y: 0.0)

UIView.animate(withDuration: 1.0, animations: {

viewT.transform = CGAffineTransform.identity

}) { (_) in

4.2.4动画结束后通知transitionContext动画完成

transitionContext.completeTransition(true)

}

}

}

以上就完成了简单的自定义转场动画

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需要注意的几个点：

1.transitioningDelegate这个协议的代理方法

1).执行进入动画的控制器，并遵循UIViewControllerAnimatedTransitioning协议

optional public func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning?

2).执行退出动画的控制器，并遵循UIViewControllerAnimatedTransitioning协议

optional public func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning?

3).获取到推入推出的两个控制器

optional public func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController?

2.UIViewControllerAnimatedTransitioning这个协议的代理方法以及属性

1).设置动画的持续时间

public func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval

2).进行跳转动画的设置，其中transitionContext这个很重要

public func animateTransition(using transitionContext: UIViewControllerContextTransitioning)

3.transitionContext其实就是UIViewControllerContextTransitioning协议

1).存放即将展现的控制器视图的容器

public var containerView: UIView { get }

2).可以返回指定的当前控制器或者即将进入的控制器

public func viewController(forKey key: UITransitionContextViewControllerKey) -> UIViewController?

3).可以返回指定的当前控制器或者即将进入的控制器的view

public func view(forKey key: UITransitionContextViewKey) -> UIView?