Question

我学习了如何在ViewController之间创建自定义过渡。根据{{3}}这本书，我有这样的代码：

//FadeAnimator.swift
import UIKit


class FadeAnimator: NSObject, UIViewControllerAnimatedTransitioning {

    let duration = 1.0
    var presenting = true
    var originFrame = CGRect.zero

    var dismissCompletion: (()->Void)?

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

    //Setting the transition’s context
    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {

        //Adding a fade transition

        let containerView = transitionContext.containerView
        let toView = transitionContext.view(forKey: .to)!
        containerView.addSubview(toView)

        toView.alpha = 0.0
        UIView.animate(withDuration: duration,
                    animations: {
                        toView.alpha = 1.0
        },
                    completion: { _ in
                        transitionContext.completeTransition(true)
        }
        )
    }
}

我就这样使用它并且有效：

//  Screen3.swift
import UIKit

class Screen3: UIViewController, UINavigationControllerDelegate {

    let transition = FadeAnimator()

    //happens only once
    override func viewDidLoad() {
        super.viewDidLoad()
        navigationItem.title = "Hello World"
        view.backgroundColor = .blue

        self.navigationController?.delegate = self
    }

    //happens every time when shown
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        setupLayout()
    }

    private func setupLayout() {
        ....
        //btn1.clickHandler {

            let nextScreen = Screen4() //4th Screen
            nextScreen.transitioningDelegate = self as? UIViewControllerTransitioningDelegate
            self.navigationController?.pushViewController(nextScreen, animated: true)

            //self.present(nextScreen, animated: true, completion: nil)
        //}
        ....
    }

    //forward
    func animationController(forPresented presented: UIViewController,
                            presenting: UIViewController, source: UIViewController) ->
        UIViewControllerAnimatedTransitioning? {
            return transition
    }

    //backward
    func animationController(forDismissed dismissed: UIViewController) ->
        UIViewControllerAnimatedTransitioning? {
            return nil
    }
}

基于另一本教程，我创建了这样的结构：

//  Transitions.swift
import UIKit

struct Transitions {

    static func setTransitionTo(view: UIView!, from: CATransitionSubtype = .fromRight) {
        let transition = CATransition()
        transition.duration = 0.5
        transition.type = CATransitionType.push
        transition.subtype = from  //CATransitionSubtype.fromRight
        transition.timingFunction = CAMediaTimingFunction(name:CAMediaTimingFunctionName.easeInEaseOut)
        view.window!.layer.add(transition, forKey: kCATransition)
    }

    static func setFadeTransitionTo(view: UIView!) {
        //let transition = SKTransition.fade(withDuration: 0.5)
        let transition = CATransition()
        transition.duration = 0.5
        transition.type = CATransitionType.fade
        transition.timingFunction = CAMediaTimingFunction(name:CAMediaTimingFunctionName.easeInEaseOut)
        view.window!.layer.add(transition, forKey: kCATransition)
    }

}

下一个问题是：如何在animateTransition（）函数中使用CATransition获得相同的结果？

如何将CATransition与自定义UIViewControllerAnimatedTransitioning一起使用

0 个答案: