UIViewController.View.Window is null in ViewDidLoad method

Question

Regardless on which controller type (UIViewController, UITableViewController), the following line always yields null in the View

Answer 1

self.view.window will be available in viewDidAppear:

override func viewDidAppear(_ animated: Bool) {
    print(self.view.window)
    let vc = self.storyboard?.instantiateViewController(identifier: "SecondViewController") as? SecondViewController
    self.view.window?.rootViewController = vc
}