First Step

Create the boilerplate codes from the pre-existed sample code. The default template code is started with a storyboard, then the next step was to delete the storyboard.

Second Step

1. In the General, Delete main.storyboard in the Main interface field.
2. Delete the Main.storyboard and ViewController.swift from the project.

Third Step

Create the window property in AppDelegate’s init function application didFinishLaunchingWithOptions, and set the window’s rootViewController property.

    self.window = UIWindow()
    self.window!.rootViewController = UIViewController()
    self.window!.backgroundColor = UIColor.redColor()
    self.window!.makeKeyAndVisible()
    return ture