How set rootViewController in Scene Delegate iOS 13

Question

Before changes in UIKit iOS 13 how I can set rootViewController at SceneDelegate?

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window:          


        

Answer 1

If you ever find yourself needing to access the window from the delegate (both iOS12 & iO13)to change the rootviewcontroller here's a couple of extensions I use:

   extension UIViewController {
        var appDelegate: AppDelegate {
        return UIApplication.shared.delegate as! AppDelegate
    }
    
    var sceneDelegate: SceneDelegate? {
        guard let windowScene = UIApplication.shared.connectedScenes.first as? UIWindowScene,
            let delegate = windowScene.delegate as? SceneDelegate else { return nil }
         return delegate
    }
}

extension UIViewController {
    var window: UIWindow? {
        if #available(iOS 13, *) {
            guard let windowScene = UIApplication.shared.connectedScenes.first as? UIWindowScene,
                let delegate = windowScene.delegate as? SceneDelegate, let window = delegate.window else { return nil }
                   return window
        }
        
        guard let delegate = UIApplication.shared.delegate as? AppDelegate, let window = delegate.window else { return nil }
        return window
    }
}