ios - 如何在 iOS 中使用自定义转换解决此问题？

Question

我构建了一个类来实现 View Controller 之间的循环转换。当我点击按钮导航到另一个 View Controller 时，一个圆圈从按钮开始增长，直到它用新 Controller 填满屏幕。当我关闭 View Controller 时，我希望这个圆圈缩小回到原来的位置。它也在工作。唯一的问题是，当关闭正在进行时，圆圈正在缩小，屏幕背面完全是黑色的，并且在动画完成后，新的 viewController 突然出现。

下面是一些效果图:

这是自定义类的代码:

class customTransition: NSObject, UIViewControllerAnimatedTransitioning{

var duration: TimeInterval = 0.5
var startPoint = CGPoint.zero

var circle = UIView()

var circleColor = UIColor.white
enum transitMode: Int {
    case presenting, dismissing
}

var transitionMode: transitMode = .presenting

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

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {

    let container = transitionContext.containerView
    guard let to = transitionContext.view(forKey: UITransitionContextViewKey.to) else {return}
    guard let from = transitionContext.view(forKey: UITransitionContextViewKey.from) else {return}

    circleColor = to.backgroundColor ?? UIColor.white

    if transitionMode == .presenting {
        to.translatesAutoresizingMaskIntoConstraints = false
        to.center = startPoint

        circle = UIView()
        circle.backgroundColor = circleColor
        circle.frame = getFrameForCircle(rect: to.frame)
        circle.layer.cornerRadius = circle.frame.width / 2
        circle.transform = CGAffineTransform(scaleX: 0.01, y: 0.01)
        circle.alpha = 0


        circle.addSubview(to)

        to.centerXAnchor.constraint(equalTo: circle.centerXAnchor).isActive = true
        to.centerYAnchor.constraint(equalTo: circle.centerYAnchor).isActive = true
        to.widthAnchor.constraint(equalToConstant: to.frame.width).isActive = true
        to.heightAnchor.constraint(equalToConstant: to.frame.height).isActive = true

        container.addSubview(circle)

        UIView.animate(withDuration: duration, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: UIView.AnimationOptions.curveLinear, animations: {
            self.circle.center = from.center
            self.circle.transform = CGAffineTransform.identity
            self.circle.alpha = 1

        }) { (sucess) in

            transitionContext.completeTransition(sucess)

        }

    } else if transitionMode == .dismissing {


        UIView.animate(withDuration: duration, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: UIView.AnimationOptions.curveLinear, animations: {
            self.circle.center = self.startPoint
            self.circle.transform = CGAffineTransform(scaleX: 0.001, y: 0.001)
            self.circle.alpha = 0

        }) { (sucess) in
            transitionContext.completeTransition(sucess)
        }
    }
}




func getFrameForCircle(rect: CGRect) -> CGRect{
    let width = Float(rect.width)
    let height = Float(rect.height)

    let diameter = CGFloat(sqrtf(width * width + height * height))

    let x: CGFloat = rect.midX - (diameter / 2)
    let y: CGFloat = rect.midY - (diameter / 2)

   return CGRect(x: x, y: y, width: diameter, height: diameter)
}



}

和实现...

    let circularTransition = customTransition()

当前 View Controller 的调用...我试图设置 secondVC.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext 但是当我设置这一行时它完全忽略了动画转换我不知道为什么。 ..`

 @objc func handlePresent(sender: UIButton){
    let secondVC = nextVC()
    secondVC.transitioningDelegate = self
    present(secondVC, animated: true, completion: nil)

}

委托(delegate)方法:

  func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    circularTransition.startPoint = presentButton.center
    circularTransition.transitionMode = .presenting
    return circularTransition
}

func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
    circularTransition.transitionMode = .dismissing
    circularTransition.startPoint = presentButton.center

    return circularTransition
}

我在这里错过了什么？有什么建议么？不使用 Storyboard，仅使用代码。

Answer 1

如果不使用navigationController，需要在presentedviewController中使用.custom模式。

 import UIKit

            class TransViewController: UIViewController {

                override func viewDidLoad() {
                    super.viewDidLoad()

                    // Do any additional setup after loading the view.
                }
                 let circularTransition = customTransition()

                @IBOutlet var presentButton : UIButton!

             @IBAction   func handlePresent(sender: UIButton){

                if let secondVC = storyboard?.instantiateViewController(withIdentifier: "next"){
                    secondVC.modalPresentationStyle = .custom
                    secondVC.transitioningDelegate = self
                    present(secondVC, animated: true, completion: nil)
                }
                }

            }


            class BackViewController: UIViewController {

                @IBAction   func dismissMe(sender: UIButton){
                    self.dismiss(animated: true, completion: nil)
                    }

            }

            extension TransViewController: UIViewControllerTransitioningDelegate {

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

                    circularTransition.startPoint = presentButton.center
                    circularTransition.transitionMode = .presenting
                    return circularTransition
                }

                func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
                    circularTransition.transitionMode = .dismissing
                    circularTransition.startPoint = presentButton.center

                    return circularTransition
                }

            }

如果没有 from 或 to view，我们就使用 from 和 to view from containView。

   func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {

    let container = transitionContext.containerView
    var to : UIView!
    var from : UIView!
    to = transitionContext.view(forKey: UITransitionContextViewKey.to)
    if to == nil {to = container}
    from = transitionContext.view(forKey: UITransitionContextViewKey.from)
    if from == nil {from = container}

其余相同:

 circleColor = to.backgroundColor ?? UIColor.white

    if transitionMode == .presenting {
        to.translatesAutoresizingMaskIntoConstraints = false
        to.center = startPoint

        circle = UIView()
        circle.backgroundColor = circleColor
        circle.frame = getFrameForCircle(rect: to.frame)
        circle.layer.cornerRadius = circle.frame.width / 2
        circle.transform = CGAffineTransform(scaleX: 0.01, y: 0.01)
        circle.alpha = 0


        circle.addSubview(to)

        to.centerXAnchor.constraint(equalTo: circle.centerXAnchor).isActive = true
        to.centerYAnchor.constraint(equalTo: circle.centerYAnchor).isActive = true
        to.widthAnchor.constraint(equalToConstant: to.frame.width).isActive = true
        to.heightAnchor.constraint(equalToConstant: to.frame.height).isActive = true

        container.addSubview(circle)

        UIView.animate(withDuration: duration, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: UIView.AnimationOptions.curveLinear, animations: {
            self.circle.center = from.center
            self.circle.transform = CGAffineTransform.identity
            self.circle.alpha = 1

        }) { (sucess) in

            transitionContext.completeTransition(sucess)

        }

    } else if transitionMode == .dismissing {


        UIView.animate(withDuration: duration, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 0, options: UIView.AnimationOptions.curveLinear, animations: {
            self.circle.center = self.startPoint
            self.circle.transform = CGAffineTransform(scaleX: 0.001, y: 0.001)
            self.circle.alpha = 0

        }) { (sucess) in
            transitionContext.completeTransition(sucess)
        }
    }
}