(UIApplication *)application willFinishLaunchingWithOptions:(NSDictionary *)launchOptions你可以通过编程方式设置(BOOL)应用程序中的关键窗口的rootViewController

例如:

- (BOOL)application:(UIApplication *)application willFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    if (shouldShowAnotherViewControllerAsRoot) {
        UIStoryboard *storyboard = self.window.rootViewController.storyboard;
        UIViewController *rootViewController = [storyboard instantiateViewControllerWithIdentifier:@"rootNavigationController"];
        self.window.rootViewController = rootViewController;
        [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

Xcode 12.4 Swift 5

在SceneDelegate.Swift

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    guard let windowScene = (scene as? UIWindowScene) else { return }
    let window = UIWindow(windowScene: windowScene)
    let storyboard = UIStoryboard(name: "Main", bundle: nil)
    window.rootViewController = storyboard.instantiateViewController(withIdentifier: "UserViewController") as! UserViewController
    
    self.window = window
    window.makeKeyAndVisible()
}

你可以添加视图控制器场景将要显示的条件

几天前我也遇到了同样的情况。一个非常简单的技巧解决了这个问题。 我设置在launch2之前隐藏我的初始视图控制器。如果初始视图控制器是正确的控制器，它在viewDidLoad中被设置为可见。否则，执行一个segue到所需的视图控制器。它在iOS 6.1及以上版本运行良好。我确信它适用于早期版本的iOS。

使用storyboard(而不是Main)设置初始ViewController

[Swift 5和Xcode 11]

主要。>属性检查器->取消勾选初始视图控制器 应用程序目标->通用->删除所有从主界面 编辑App委托

@main
class AppDelegate: UIResponder, UIApplicationDelegate {
    
    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        self.window = UIWindow(frame: UIScreen.main.bounds)
        
        let storyboard: UIStoryboard = UIStoryboard(name: "SomeStoryboard", bundle: nil) //SomeStoryboard  is name of .storyboard
        let viewController: ViewController = storyboard.instantiateViewController(withIdentifier: "someStoryboardId") as! ViewController //someStoryboardId is Storyboard ID

        self.window?.rootViewController = viewController
        self.window?.makeKeyAndVisible()

        return true
    }
}

Swift 5或以上版本#创建路由视图控制器 如果你使用xcode 11或以上版本，首先初始化var window: UIWindow?在AppDelegate

let rootVC = mainStoryboard.instantiateViewController(withIdentifier: "YOURCONTROLLER") as! YOURCONTROLLER

        navigationController.setNavigationBarHidden(true, animated: true)
        UIApplication.shared.windows.first?.rootViewController = UINavigationController.init(rootViewController: rootVC)
        UIApplication.shared.windows.first?.makeKeyAndVisible()