ios - 自定义 UIViewController 动画问题

Question

UIViewController我为with创建了一个简单的自定义过渡动画UIViewControllerAnimatedTransitioning。一切正常，但是当目标视图出现时，内容从右下角开始出现，当视图消失时，内容从左上角消失。我附上了 gif 示例。这是我的代码：

CustomViewAnimator.swift

class CustomViewAnimator: NSObject, UIViewControllerAnimatedTransitioning {

    private let interval = 0.5
    var forward = false
    var originFrame: CGRect = .zero

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

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {

        let containerView = transitionContext.containerView

        guard let toView = transitionContext.view(forKey: .to) else {return}
        guard let fromView = transitionContext.view(forKey: .from) else {return}
        let destinationView = forward ? toView : fromView
        destinationView.alpha = forward ? 0 : 1

        forward ? containerView.addSubview(toView) : containerView.insertSubview(toView, belowSubview: fromView)
        forward ? (destinationView.frame = originFrame) : (destinationView.frame = fromView.frame)

        UIView.animate(withDuration: interval, animations: {

            self.forward ? (destinationView.frame = fromView.frame) : (destinationView.frame = self.originFrame)
            destinationView.alpha = self.forward ? 1 : 0

        }) { (finished) in
            transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
        }

    }

}

MainViewController.self

class MainViewController: UIViewController {

    private var button: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
        setup()
    }

    @objc private func openView() {
        let viewController = TargetViewController()
        viewController.transitioningDelegate = self
        navigationController?.pushViewController(viewController, animated: true)

    }
}

extension MainViewController: UINavigationControllerDelegate {
    func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationController.Operation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {

        let animator = CustomViewAnimator()
        animator.originFrame = button.frame
        animator.forward = (operation == .push)
        return animator
    }
}

extension MainViewController: UIViewControllerTransitioningDelegate {
    func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        let animator = CustomViewAnimator()
        animator.forward = true
        return animator
    }

    func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        let animator = CustomViewAnimator()
        animator.forward = false
        return animator
    }
}

TargetViewController.swift

class TargetViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        setup()
    }

}

extension TargetViewController {

    fileprivate func setup() {
        view.backgroundColor = .orange
        navigationItem.title = "Target view"

        let label: UILabel = {
            let label = UILabel()
            label.translatesAutoresizingMaskIntoConstraints = false
            label.text = "Hello from target view :)"
            label.textColor = .white
            label.font = UIFont.boldSystemFont(ofSize: 18)
            return label
        }()
        view.addSubview(label)

        label.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        label.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
    }

}

谁能说我如何解决这个问题，所以 TargetViewController 中的标签（或任何其他内容）保持固定在他们的位置上？

标签： iosswiftanimationuiviewcontroller

Answer 1

我同意其他答案的讨论。我的建议是不要为 UIView 的框架设置动画，您可以为目标视图的掩码设置动画，如下所示。应该是操作者真正想要的效果。

粗体部分是与原帖的区别。

 func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {

    let containerView = transitionContext.containerView

    guard let toView = transitionContext.view(forKey: .to) else {return}
    guard let fromView = transitionContext.view(forKey: .from) else {return}
    let destinationView = forward ? toView : fromView
    destinationView.alpha = forward ? 0 : 1

让 maskView = UIView.init(frame: forward ? originFrame : fromView.frame)

maskView.backgroundColor = UIColor.white

destinationView.mask = maskView

    forward ? containerView.addSubview(toView) : containerView.insertSubview(toView, belowSubview: fromView)
    forward ? (destinationView.frame = toView.frame) : (destinationView.frame = fromView.frame)


    UIView.animate(withDuration: interval, animations: {

自我转发？(destinationView.mask?.frame = fromView.frame) : (destinationView.mask?.frame = self.originFrame)

        destinationView.alpha = self.forward ? 1 : 0
            }) { (finished) in

        transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
    }

}