打开mainstoryboard，首先选择要启动的视图，然后打开Utilities—> Attributes。在“视图控制器”下面，你会看到“Is initial View Controller”单选按钮。选择它。

——对修改后的问题:

也许你可以试试这个:在你的初始视图的ViewDidLoad部分写一个方法，当这个方法在应用程序启动时运行，方法触发一个到另一个视图的segue。

我创建了一个路由类来处理动态导航和保持干净的AppDelegate类，我希望它也能帮助其他。

//
//  Routing.swift
// 
//
//  Created by Varun Naharia on 02/02/17.
//  Copyright © 2017 TechNaharia. All rights reserved.
//

import Foundation
import UIKit
import CoreLocation

class Routing {

    class func decideInitialViewController(window:UIWindow){
        let userDefaults = UserDefaults.standard
        if((Routing.getUserDefault("isFirstRun")) == nil)
        {
            Routing.setAnimatedAsInitialViewContoller(window: window)
        }
        else if((userDefaults.object(forKey: "User")) != nil)
        {
            Routing.setHomeAsInitialViewContoller(window: window)
        }
        else
        {
            Routing.setLoginAsInitialViewContoller(window: window)
        }

    }

    class func setAnimatedAsInitialViewContoller(window:UIWindow) {
        Routing.setUserDefault("Yes", KeyToSave: "isFirstRun")
        let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let animatedViewController: AnimatedViewController = mainStoryboard.instantiateViewController(withIdentifier: "AnimatedViewController") as! AnimatedViewController

        window.rootViewController = animatedViewController
        window.makeKeyAndVisible()
    }

    class func setHomeAsInitialViewContoller(window:UIWindow) {
        let userDefaults = UserDefaults.standard
        let decoded  = userDefaults.object(forKey: "User") as! Data
        User.currentUser = NSKeyedUnarchiver.unarchiveObject(with: decoded) as! User

        if(User.currentUser.userId != nil && User.currentUser.userId != "")
        {
            let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
            let homeViewController: HomeViewController = mainStoryboard.instantiateViewController(withIdentifier: "HomeViewController") as! HomeViewController
            let loginViewController: UINavigationController = mainStoryboard.instantiateViewController(withIdentifier: "LoginNavigationViewController") as! UINavigationController
            loginViewController.viewControllers.append(homeViewController)
            window.rootViewController = loginViewController
        }
        window.makeKeyAndVisible()
    }

    class func setLoginAsInitialViewContoller(window:UIWindow) {
        let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let loginViewController: UINavigationController = mainStoryboard.instantiateViewController(withIdentifier: "LoginNavigationViewController") as! UINavigationController

        window.rootViewController = loginViewController
        window.makeKeyAndVisible()
    }

  class func setUserDefault(_ ObjectToSave : Any?  , KeyToSave : String)
    {
        let defaults = UserDefaults.standard

        if (ObjectToSave != nil)
        {

            defaults.set(ObjectToSave, forKey: KeyToSave)
        }

        UserDefaults.standard.synchronize()
    }

    class func getUserDefault(_ KeyToReturnValye : String) -> Any?
    {
        let defaults = UserDefaults.standard

        if let name = defaults.value(forKey: KeyToReturnValye)
        {
            return name as Any
        }
        return nil
    }

    class func removetUserDefault(_ KeyToRemove : String)
    {
        let defaults = UserDefaults.standard
        defaults.removeObject(forKey: KeyToRemove)
        UserDefaults.standard.synchronize()
    }

}

在AppDelegate中调用这个

 self.window = UIWindow(frame: UIScreen.main.bounds)
 Routing.decideInitialViewController(window: self.window!)

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;
}

我认为这是不可能的。 相反，你可以有一个初始控制器它有segue到不同的视图控制器。在启动时，您可以决定以编程方式执行哪个segue。

找到了简单的解决方案-不需要从故事板和编辑项目信息选项卡中删除“初始视图控制器检查”，并使用makeKeyAndVisible，只是放置

self.window.rootViewController = rootVC;

in

- (BOOL) application:didFinishLaunchingWithOptions:

您可以使用接口生成器以及编程方式设置初始视图控制器。

下面是编程使用的方法。

objective - c:

        self.window = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];
        UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];

        UIViewController *viewController = [storyboard instantiateViewControllerWithIdentifier:@"HomeViewController"]; // <storyboard id>

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

        return YES;

迅速:

        self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
        let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)

        var objMainViewController: MainViewController = mainStoryboard.instantiateViewControllerWithIdentifier("MainController") as! MainViewController

        self.window?.rootViewController = objMainViewController

        self.window?.makeKeyAndVisible()

        return true