Swift segue 过渡阴影

Question

我正在使用故事板中的一些标准转场，它们每个都有相同的背景颜色。我遇到的问题是，当转场过渡接近完成时，整个帧周围会出现类似背景的暗阴影。

它非常微弱，但足以引起问题。有没有人遇到过这种情况？

Answer 1

标准的导航控制器推送/弹出动画会使您从中推送的视图和您要弹出的视图变暗。如果您不喜欢这样，您可以自定义过渡，使用仅滑动视图进出的动画，但不会使任何内容变暗：

// this is the view controller you are pushing from

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationController?.delegate = self
    }

}

// make the view controller conform to `UINavigationControllerDelegate`

extension ViewController: UINavigationControllerDelegate {
    func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationControllerOperation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return PushPopAnimator(operation: operation)
    }
}

// The animation controller

class PushPopAnimator: NSObject, UIViewControllerAnimatedTransitioning {
    let operation: UINavigationControllerOperation

    init(operation: UINavigationControllerOperation) {
        self.operation = operation
        super.init()
    }

    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.5
    }

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        let from = transitionContext.viewController(forKey: .from)!
        let to   = transitionContext.viewController(forKey: .to)!

        let rightTransform = CGAffineTransform(translationX: transitionContext.containerView.bounds.size.width, y: 0)
        if operation == .push {
            to.view.transform = rightTransform
            transitionContext.containerView.addSubview(to.view)
            UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: { 
                to.view.transform = .identity
            }, completion: { finished in
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
            })
        } else if operation == .pop {
            to.view.transform = .identity
            transitionContext.containerView.insertSubview(to.view, belowSubview: from.view)
            UIView.animate(withDuration: transitionDuration(using: transitionContext), animations: {
                from.view.transform = rightTransform
            }, completion: { finished in
                from.view.transform = .identity
                transitionContext.completeTransition(!transitionContext.transitionWasCancelled)
            })
        }
    }
}

有关使用视图控制器的自定义转换的信息，请参阅 WWDC 2013 视频Custom Transitions Using View Controllers。