iOS 13: Swift - 'Set application root view controller programmatically' does not work

Question

I have following code in my AppDelegate.swift to setup root view controller for an iOS application. But it does not work. It follows Target structure (defined under General

Answer 1

For Xcode 11+ and Swift 5+ inside SceneDelegate.swift

var window: UIWindow?

    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)
            let submodules = (
                home: HomeRouter.createModule(),
                search: SearchRouter.createModule(),
                exoplanets: ExoplanetsRouter.createModule()
            )
            
            let tabBarController = TabBarModuleBuilder.build(usingSubmodules: submodules)
            
            window.rootViewController = tabBarController
            self.window = window
            window.makeKeyAndVisible()
        }
    }

Answer 2

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

    guard let windowScene = (scene as? UIWindowScene) else { return }
    self.window = UIWindow(windowScene: windowScene)               
      self.window?.makeKeyAndVisible()

    let layout = UICollectionViewFlowLayout()
    let swipingController = SwipingController(collectionViewLayout: layout)
          self.window?.rootViewController = swipingController       

}

Answer 3

I tried the following approach and it's working for me in iOS 13 and also tested on iOS 12.4.2 from Xcode 11.

func resetRoot() {
            guard let rootVC = UIStoryboard.init(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "ViewController") as? ViewController else {
                return
            }
            let navigationController = UINavigationController(rootViewController: rootVC)

            UIApplication.shared.windows.first?.rootViewController = navigationController
            UIApplication.shared.windows.first?.makeKeyAndVisible()
     }

Answer 4

If you don't want to use main storyboard, if you want to create you own views programmatically.

For xcode 11.

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

    guard let windowScene = (scene as? UIWindowScene) else { return }
    window = UIWindow(windowScene: windowScene)
    window?.makeKeyAndVisible()
    window?.rootViewController = UINavigationController(rootViewController:      ViewController())
}

This will defenetily work. Thanks

Answer 5

I did two things. Firstly I set a Notification into SceneDelegate, then when I needed to change the RootViewController I did a Notification Post and it worked. But it's an anwful solution.

After that

My boss recommended me to change the Controllers of the NavigationController, something like this:

func logged() {
    let mainStoryboard: UIStoryboard = UIStoryboard(name: "MainTabViewController", bundle: nil)
    let mainVC = mainStoryboard.instantiateInitialViewController()

    self.navigationController?.setViewControllers([mainVC!], animated: false)
}

I know that perhaps it's not the best solution, but I see it cleaner.
I'm working now on iOS 13 and I didn't want to use deprecated things.

Answer 6

Here's what work for both iOS 13.x and iOS 12.x and below

For iOS 13,In the Scene Delegate

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
            guard let windowScene = (scene as? UIWindowScene) else { return }
            self.window = UIWindow(frame: windowScene.coordinateSpace.bounds)
           //Make sure to do this else you won't get 
           //the windowScene object using UIApplication.shared.connectedScenes
            self.window?.windowScene = windowScene 
            let storyBoard: UIStoryboard = UIStoryboard(name: storyBoardName, bundle: nil)
            window?.rootViewController = storyBoard.instantiateInitialViewController()
            window?.makeKeyAndVisible()
        }

In a utility class, I wrote below function to get the window object and assign it to the appdelegate.window. According to my needs, I needed to set root view controller at multiple places in different scenarios for which I needed the window object.

static func redirectToMainNavRVC(currentVC: UIViewController){
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        let vc = UIStoryboard(name: appDelegate.storyBoardName, bundle: nil).instantiateViewController(withIdentifier: "MainNavigationViewController") as! MainNavigationViewController
    if #available(iOS 13.0, *){
        if let scene = UIApplication.shared.connectedScenes.first{
            guard let windowScene = (scene as? UIWindowScene) else { return }
            print(">>> windowScene: \(windowScene)")
            let window: UIWindow = UIWindow(frame: windowScene.coordinateSpace.bounds)
            window.windowScene = windowScene //Make sure to do this
            window.rootViewController = vc
            window.makeKeyAndVisible()
            appDelegate.window = window
        }
    } else {
        appDelegate.window?.rootViewController = vc
        appDelegate.window?.makeKeyAndVisible()
    }
}

This worked well for me. Hopefully, it works for others too.