How to resolve: 'keyWindow' was deprecated in iOS 13.0

Question

I'm using Core Data with Cloud Kit, and have therefore to check the iCloud user status during application startup. In case of problems I want to issue a dialog to the user, and I do it using UIApplication.shared.keyWindow?.rootViewController?.present(...) up to now.

In Xcode 11 beta 4, there is now a new deprecation message, telling me:

'keyWindow' was deprecated in iOS 13.0: Should not be used for applications that support multiple scenes as it returns a key window across all connected scenes

How shall I present the dialog instead?

Answer 1

This is my solution:

let keyWindow = UIApplication.shared.connectedScenes
        .filter({$0.activationState == .foregroundActive})
        .map({$0 as? UIWindowScene})
        .compactMap({$0})
        .first?.windows
        .filter({$0.isKeyWindow}).first

Usage e.g.:

keyWindow?.endEditing(true)

Answer 2

I have implemented this solution for single-window apps:

var mainWindow: UIWindow? {
    if #available(iOS 13.0, *) {
        if let windowScene = UIApplication.shared.connectedScenes.first as? UIWindowScene {
            return windowScene.windows.first
        }
    }
    return UIApplication.shared.keyWindow
}