swift - 在 iOS 13、Xcode 11 中呈现 View Controller 的问题

Question

我正在尝试在 topMostViewController 上呈现一个 View Controller 。它适用于 iOS 12 及更低版本。但是在 iOS 13 上我收到了这个错误:

Manually adding the rootViewController's view to the view hierarchy is no longer supported. Please allow UIWindow to add the rootViewController's view to the view hierarchy itself.

我已经检查了 iOS 12 及更低版本，下面的代码工作正常。但是在 iOS 13 上，我无法呈现 View Controller 。我在 viewDidLoad 上打印；它正在打印，但未显示 View 。

func presentInWindow(animated flag: Bool = true, completion: (() -> Void)? = nil) {

        DispatchQueue.main.async {
            var alertWindow: UIWindow?
            alertWindow = UIWindow(frame: UIScreen.main.bounds)
            alertWindow?.windowLevel = UIWindow.Level.alert + 1
            alertWindow?.rootViewController = UIApplication.topViewController()
            if let rootViewController = alertWindow?.rootViewController {
                alertWindow?.makeKeyAndVisible()
                rootViewController.present(self, animated: flag, completion: completion)
            }
        }

}

static func topViewController() -> UIViewController? {

        var topViewController: UIViewController?

        if #available(iOS 13.0, *) {

            topViewController = shared.connectedScenes
                .filter({$0.activationState == .foregroundActive})
                .map({$0 as? UIWindowScene})
                .compactMap({$0})
                .first?.windows
                .filter({$0.isKeyWindow}).first?.rootViewController
        } else {
            topViewController = shared.delegate?.window??.rootViewController
        }

        while true {
            if let presented = topViewController?.presentedViewController {
                topViewController = presented
            } else if let nav = topViewController as? UINavigationController {
                topViewController = nav.visibleViewController
            } else {
                break
            }
        }

        return topViewController
}

Answer 1

此代码将用于在顶部创建一个 View Controller 。您可以在此行调整 View Controller 的大小:popOverVC.view.frame = lSs 我不确定这段代码是否正是您所要求的，但如果您需要快速解决方案，它将在 swift 5、iOS 13 和 xcode 11 中呈现 View Controller 。请注意，它是一个 subview Controller ，因此如果您删除父 View Controller ，它也会离开。只需将 self 更改为您想要展示的 ViewController。

    let popOverVC = UIStoryboard(name: "yourSB", bundle: nil).instantiateViewController(withIdentifier: "vcYouWantID") as! vcYouWant
    self.addChild(popOverVC)
    let lSs = UIScreen.main.bounds
    popOverVC.view.frame = lSs
    popOverVC.view.tag = tag
    self.view.addSubview(popOverVC.view)
    popOverVC.didMove(toParent: self)