App startup without storyboard - UIViewController is still not visible - ios

Question

After reading https://medium.com/ios-os-x-development/ios-start-an-app-without-storyboard-5f57e3251a25
I have performed the following steps
Remove Main.storyboard and LaunchScreen.storyboard from the project
Remove Main from Main Interface under Deployment Info
Remove reference to Main.storyboard and LaunchScreen.storyboard from Info.plist
Here's some screenshots of the above steps
In AppDelegate.swift, I have make the following modification
import UIKit
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
window = UIWindow(frame: UIScreen.main.bounds)
let viewController = ViewController()
viewController.view.backgroundColor = UIColor.red
window!.rootViewController = viewController
window!.makeKeyAndVisible()
print("application executed")
return true
}
}
When I launch the simulator, the "application executed" is printed at console.
I am expecting to see a full screen red color once the app launched. However, I only can see an entire black screen.
May I know what else steps I have missed out?

Answer 1

You have scene life-cycle, so window should be created in SceneDelegate.
Here is AppDelegate:
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
return true
}
func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
}
}
and now here is SceneDelegate
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
var window: UIWindow?
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
if let windowScene = scene as? UIWindowScene {
let viewController = ViewController()
viewController.view.backgroundColor = UIColor.red
let window = UIWindow(windowScene: windowScene)
window.rootViewController = viewController
self.window = window
window.makeKeyAndVisible()
}
}
}