Hi All, I'm new(ish) to Swift, having learnt it to a rudimentary level about 4 years ago, and now following this excellent course to remind me of everything I have now completely forgotten. I seem to be following everything reasonably well so far, but the code in this exercise is causing me a compile error as below. Could be something I've buggered up somewhere else, but have been scratching my head trying various things with little success...

if let tabBarController = window?.rootViewController as? UITabBarController {
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    let vc = storyboard.instantiateViewController(withIdentifier: "NavController")
    vc.tabBarItem = UITabBarItem(tabBarSystemItem: .topRated, tag: 1)
    tabBarController.viewControllers?.append(vc)
}

The first line of this is giving me compile error "Use of unresolved identifier 'window'" Any thoughts would be very much appreciated!

Cheers

Lovely job, that's sorted it! Cheers

I ran into this also! After experimenting for a while, I found 2 ways to get the project to run!

First way to correct: In the appDelegate.swift file add this line below the class: "var window: UIWindow?" Now the project would run but the Top Rated button was not visible! To get the button to show: Open info.plist and delete the key "Application Scene Manifest".

The button does appear and works but I did not think this was the best solution!

Second way to make the button visible is the way @roosterboy pointed out. That is the way I decided to use.

I also used @roosterboy's solution, and that resolved my problem. For what it's worth, I inserted the code in the scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) function.