在addDelegate.wift 文件里面修改

 

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

        // Override point for customization after application launch.

        

        var loginCtl : LoginViewController!

        self.window = UIWindow(frame: UIScreen.mainScreen().bounds);

        self.window?.backgroundColor = UIColor.whiteColor();

        loginCtl = LoginViewController(nibName:"LoginViewController",bundle:NSBundle.mainBundle());

        self.window?.rootViewController = loginCtl;

        self.window?.makeKeyAndVisible();

        

        return true

    }

 

我这是启动了 LoginViewController.xib