Swift segue过渡阴影

Question

我正在使用故事板中的一些标准segue，它们各自具有相同的背景颜色。我遇到的问题是，当segue过渡接近完成时，整个画面周围会出现像背景一样的暗影。

它非常微弱，但足以引起问题。有没有人遇到过这个？

Answer 1

标准导航控制器推/动画动画会使您正在推动的视图和您要弹出的视图变暗。如果你不喜欢这样，你可以使用只是滑入视图的动画来自定义过渡，但不会变暗任何东西：

// 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。