选择要首先打开的视图控制器，然后转到属性检查器。 转到初始场景，检查初始视图控制器选项。

这是你的初始视图控制器在应用启动时首先打开。

如何没有一个虚拟的初始视图控制器

确保所有初始视图控制器都有一个故事板ID。

在故事板中，取消选中第一个视图控制器的“Is initial View Controller”属性。

如果你在这个时候运行你的应用，你会看到:

失败的实例化默认视图控制器UIMainStoryboardFile 'MainStoryboard' -也许指定的入口点没有设置?

你会注意到你在app委托中的window属性现在是nil。

在应用程序的设置中，转到目标和信息选项卡。这里清除了主线故事板文件基本名称的值。在“常规”页签中，清除“主界面”的值。这将删除警告。

在应用委托的应用程序中创建窗口和所需的初始视图控制器:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];

    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];

    UIViewController *viewController = // determine the initial view controller here and instantiate it with [storyboard instantiateViewControllerWithIdentifier:<storyboard id>];

    self.window.rootViewController = viewController;
    [self.window makeKeyAndVisible];

    return YES;
}

你可以将Navigation rootviewcontroller设置为一个主视图控制器。 这个想法可以用于根据应用程序需求自动登录。

UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];

UIViewController viewController = (HomeController*)[mainStoryboard instantiateViewControllerWithIdentifier: @"HomeController"];

UINavigationController navController = [[UINavigationController alloc] initWithRootViewController:viewController];

 self.window.rootViewController = navController;

if (NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_6_1) {

    // do stuff for iOS 7 and newer

    navController.navigationBar.barTintColor = [UIColor colorWithRed:88/255.0 green:164/255.0 blue:73/255.0 alpha:1.0];

    navController.navigationItem.leftBarButtonItem.tintColor = [UIColor colorWithRed:88/255.0 green:164/255.0 blue:73/255.0 alpha:1.0];

    navController.navigationBar.tintColor = [UIColor whiteColor];

    navController.navigationItem.titleView.tintColor = [UIColor whiteColor];

    NSDictionary *titleAttributes =@{

                                     NSFontAttributeName :[UIFont fontWithName:@"Helvetica-Bold" size:14.0],

                                     NSForegroundColorAttributeName : [UIColor whiteColor]

                                     };

    navController.navigationBar.titleTextAttributes = titleAttributes;

    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];

}

else {

    // do stuff for older versions than iOS 7

    navController.navigationBar.tintColor = [UIColor colorWithRed:88/255.0 green:164/255.0 blue:73/255.0 alpha:1.0];



    navController.navigationItem.titleView.tintColor = [UIColor whiteColor];

}

[self.window makeKeyAndVisible];

对于StoryboardSegue用户

UIStoryboard *mainStoryboard = [UIStoryboard storyboardWithName:@"Main" bundle: nil];

// Go to Login Screen of story board with Identifier name : LoginViewController_Identifier

LoginViewController *loginViewController = (LoginViewController*)[mainStoryboard instantiateViewControllerWithIdentifier:@“LoginViewController_Identifier”];

navigationController = [[UINavigationController alloc] initWithRootViewController:testViewController];

self.window.rootViewController = navigationController;

[self.window makeKeyAndVisible];

// Go To Main screen if you are already Logged In Just check your saving credential here

if([SavedpreferenceForLogin] > 0){
    [loginViewController performSegueWithIdentifier:@"mainview_action" sender:nil];
}

谢谢

斯威夫特5

如果你没有一个ViewController设置为storyboard中的初始ViewController，你需要做两件事:

进入你的项目TARGETS，选择你的项目-> General ->清除Main Interface字段。 总是在项目TARGETS中，现在转到Info ->应用场景清单->场景配置->应用程序会话角色-> Item0(默认配置)->删除故事板名称字段。

最后，你现在可以在SceneDelegate中添加你的代码:

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
    // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
    // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
    guard let windowScene = (scene as? UIWindowScene) else { return }

    window = UIWindow(windowScene: windowScene)


    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    // Make sure you set an Storyboard ID for the view controller you want to instantiate
    window?.rootViewController = storyboard.instantiateViewController(withIdentifier: identifier)
    window?.makeKeyAndVisible()

}

对于所有喜欢霉霉的人，下面是@Travis用Swift翻译的答案:

做@Travis在Objective C代码之前解释的事情。然后,

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

    self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
    let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
    var exampleViewController: ExampleViewController = mainStoryboard.instantiateViewControllerWithIdentifier("ExampleController") as! ExampleViewController

    self.window?.rootViewController = exampleViewController

    self.window?.makeKeyAndVisible()

    return true
}

ExampleViewController将是您想要显示的新的初始视图控制器。

步骤解释如下:

创建一个与当前窗口大小相同的新窗口，并将其设置为主窗口 实例化一个故事板，我们可以用它来创建新的初始视图控制器 基于Storyboard ID实例化我们新的初始视图控制器 将新窗口的根视图控制器设置为我们刚刚启动的新控制器 使新窗口可见

享受和快乐的编程!

 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        self.window = UIWindow(frame: UIScreen.main.bounds)
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        if (PreferenceHelper.getAccessToken() != "") {
            let initialViewController = storyboard.instantiateViewController(withIdentifier: "your View Controller Identifier")
            self.window?.rootViewController = initialViewController
        } else {
            let initialViewController = storyboard.instantiateViewController(withIdentifier: "your View Controller identifier")
            self.window?.rootViewController = initialViewController
        }
        self.window?.makeKeyAndVisible()
        return true
    }

/*
use your view Controller identifier must use it doubles quotes**strong text**