Swift AppDelegate 套路代码

自定义入口总结
1.不是navigation的

    var window: UIWindow?
    var viewController: UIViewController?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        self.window = UIWindow.init(frame: UIScreen.main.bounds)
        let vc = ViewController()
        self.viewController = vc
        self.window?.rootViewController = self.viewController
        self.window?.makeKeyAndVisible()
        return true
    }

2.navigation

    var window: UIWindow?
    var nav : UINavigationController?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        self.window = UIWindow.init(frame: UIScreen.main.bounds)
        nav = UINavigationController.init();
        nav?.viewControllers = [LoginViewController()];
        self.window?.rootViewController = nav
        self.window?.makeKeyAndVisible()
        return true
    }