ios - 如何在不关闭父/第一个 View Controller 的情况下以模态方式呈现 View Controller

Question

我正在尝试在原始 UIViewController 上为 UICollectionViewController 设置动画，并将原始 UIViewController 模糊为背景，但是，每次动画结束后，我可以通过模糊的 View 清楚地看到原始 View Controller 已被关闭，我该怎么做才能避免第一个 UIViewController 被关闭？

在第一个 View Controller 中显示第二个 View Controller 的代码:

let VC = storyboard?.instantiateViewController(withIdentifier: "PopoverCollectionVC") as! PopoverCollectionVC
VC.setDataSource(with: .calcDPSItems)
VC.collectionView?.backgroundColor = UIColor.clear
VC.transitioningDelegate = self
self.present(VC, animated: true, completion: nil)

animator 对象中用于自定义动画的代码:

func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
    let containerView = transitionContext.containerView
    let fromView = transitionContext.view(forKey: .from)!
    let toView = transitionContext.view(forKey: .to)!

    if presenting {
        // configure blur
        effectView.frame = fromView.bounds
        containerView.addSubview(effectView)
        // configure collection view
        toView.frame = CGRect(x: 0, y: fromView.frame.height, width: fromView.frame.width, height: fromView.frame.height / 2)
        containerView.addSubview(toView)

        UIView.animateKeyframes(withDuration: duration, delay: 0, options: .calculationModeCubic, animations: {

            UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 0.6) {
                toView.center.y = fromView.center.y
            }

            UIView.addKeyframe(withRelativeStartTime: 0.1, relativeDuration: 1) {
                self.effectView.effect = UIBlurEffect(style: .dark)
            }

        }) { _ in
            transitionContext.completeTransition(true)
        }
    } else {

        ...
    }

Answer 1

您需要指定模态呈现样式将覆盖当前上下文:

VC.modalPresentationStyle = .overCurrentContext

然后得到你需要的呈现 View

// Get the from view from The ViewController because there is a bug in iOS when 
// using some modalPresentationStyle values 
// that causes the viewForKey to returm nil for UITransitionContextFromViewKey 
// www.splinter.com.au/2015/04/17/ios8-view-controller-transiti‌​oning-bug/ 

let fromVC = transitionContext.viewController(forKey: .from) 
let fromView = fromVC?.view