自定义 segue 过渡动画

Question

我正在开发一个利用导航控制器的应用程序。我有一个视图控制器，它在导航栏中有一个左右按钮，每个按钮都切换到不同的视图控制器。当我按下右键时，我只是呼叫self.performSegue(withIdentifier: "ToDestination", sender: nil)，当我弹出回来时，我呼叫_ = self.navigationController?.popViewController(animated: true)。

我的问题是当我按下左键时。我可以按下和弹出，但我希望过渡与右按钮相反。由于我按下了左键，我希望 segue 从左向右过渡，当我弹出时，我希望 segue 从右向左过渡。

我可以通过执行以下操作使过渡按照我想要的方式工作：

//push
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "SearchController") as! SearchController
let transition: CATransition = CATransition()
let timeFunc : CAMediaTimingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
transition.duration = 0.5
transition.timingFunction = timeFunc
transition.type = kCATransitionPush
transition.subtype = kCATransitionFromLeft
self.navigationController!.view.layer.add(transition, forKey: kCATransition)
self.navigationController!.pushViewController(vc, animated: true)
//pop
let transition: CATransition = CATransition()
let timeFunc : CAMediaTimingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
transition.duration = 0.5
transition.timingFunction = timeFunc
transition.type = kCATransitionPush
transition.subtype = kCATransitionFromRight
self.navigationController!.view.layer.add(transition, forKey: kCATransition)
_ = self.navigationController?.popViewController(animated: true)

这有效，但在视图控制器之间转换时会出现黑闪光。有没有更好的方法来获取默认过渡动画？

Answer 1

实现这一目标的最佳方法是通过符合协议创建自定义推送和弹出动画UIViewControllerAnimatedTransitioning：

//CustomPushAnimation class
import UIKit
class CustomPushAnimation: NSObject, UIViewControllerAnimatedTransitioning {
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
return 0.2
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
let containerVw = transitionContext.containerView
let fromViewController = transitionContext.viewController(forKey: .from)
let toViewController = transitionContext.viewController(forKey: .to)
guard let fromVc = fromViewController, let toVc = toViewController else { return }
let finalFrame = transitionContext.finalFrame(for: toVc)
//Below line will start from left
toVc.view.frame = finalFrame.offsetBy(dx: -finalFrame.size.width/2, dy: 0)
containerVw.addSubview(toVc.view)
UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
toVc.view.frame = finalFrame
fromVc.view.alpha = 0.5
}, completion: {(finished) in
transitionContext.completeTransition(finished)
fromVc.view.alpha = 1.0
})
}
}

//CustomPopAnimation class
import UIKit
class CustomPopAnimation: NSObject, UIViewControllerAnimatedTransitioning {
func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
return 0.2
}
func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
let containerView = transitionContext.containerView
let fromViewController = transitionContext.viewController(forKey: .from)
let toViewController = transitionContext.viewController(forKey: .to)
guard let fromVc = fromViewController,
let toVc = toViewController,
let snapshotView = fromVc.view.snapshotView(afterScreenUpdates: false)
else { return }
let finalFrame = transitionContext.finalFrame(for: fromVc)
toVc.view.frame = finalFrame
containerView.addSubview(toVc.view)
containerView.sendSubview(toBack: toVc.view)
snapshotView.frame = fromVc.view.frame
containerView.addSubview(snapshotView)
fromVc.view.removeFromSuperview()
UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
//Below line will start from right
snapshotView.frame = finalFrame.offsetBy(dx: -finalFrame.size.width, dy: 0)
}, completion: {(finished) in
snapshotView.removeFromSuperview()
transitionContext.completeTransition(finished)
})
}
}

最后，您需要展示带有设置的新视图控制器 动画标志为 true，否则将不起作用

//Below code should be inside YourViewController
let vc = UIStoryboard(name: "storyboardName", bundle: nil).instantiateViewController(withIdentifier: "ViewControllerIdentifier")            let navigationController = BaseNavigationController(rootViewController: vc)
navigationController.transitioningDelegate = self
present(navigationController, animated: true, completion: nil)

您还需要符合 UIViewControllerTransitioningDelegate 协议为了工作动画

extension YourViewController: UIViewControllerTransitioningDelegate {
func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
return customPushAnimation
}
func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
return customPopAnimation
}
}