Ios 以编程方式更改情节提要的rootViewController

我已经使用

故事板创建了我的项目。根
ViewController
位于
情节提要
中，我没有在
appDelegate
中编写任何代码

现在我想显示我的应用程序的浏览，所以我想将root
ViewController
从
tabbar
更改为我的TourVC，当应用程序浏览完成后，我想再次将我的root
ViewController
切换回
tabbar

因此，我在网上查找并遵循以下几点

1） 从app.plist文件中删除故事板，
2） 取消选中
情节提要
中的选项“isInitialViewController”，该选项在
选项卡栏
控制器的情况下被选中，因为它是根
视图控制器
，
3） 在appDelegate.m文件中添加此代码

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
ProductTourViewController *PT = [[ProductTourViewController alloc] initWithNibName:@"ProductTourViewController" bundle:nil];
self.window.rootViewController = PT;
[self.window makeKeyAndVisible];
return YES;

但我的应用程序因此错误日志而崩溃

[ProductTourViewController selectedViewController]: unrecognized selector sent to instance 0x1766a9e0

我还得到了一个警告

Unsupported Configuration: Scene is unreachable due to lack of entry points and does not have an identifier for runtime access via -instantiateViewControllerWithIdentifier:.

目标C：

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];
UITabBarController *rootViewController = [storyboard instantiateViewControllerWithIdentifier:@"tabBarcontroller"];
[[UIApplication sharedApplication].keyWindow setRootViewController:rootViewController];

斯威夫特：

 let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
 let viewController = mainStoryboard.instantiateViewControllerWithIdentifier("tabBarcontroller") as UITabBarController  
   UIApplication.sharedApplication().keyWindow?.rootViewController = viewController;

Swift 3：

let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
UIApplication.shared.keyWindow?.rootViewController = viewController

Swift 5:

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
UIApplication.shared.windows.first?.rootViewController = viewController
UIApplication.shared.windows.first?.makeKeyAndVisible()

或者简单地说：

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
self.view.window?.rootViewController = viewController
self.view.window?.makeKeyAndVisible()

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
UIApplication.shared.windows.first?.rootViewController = viewController
UIApplication.shared.windows.first?.makeKeyAndVisible()

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
self.view.window?.rootViewController = viewController
self.view.window?.makeKeyAndVisible()

两者都很好
 在主情节提要中为类设置情节提要ID

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

UINavigationController *controller = (UINavigationController*)[MainStoryboard
                                                                           instantiateViewControllerWithIdentifier: @"RootNavigationController"];


LoginViewController *login=[MainStoryboard instantiateViewControllerWithIdentifier:@"LoginViewController"];
            [controller setViewControllers:[NSArray arrayWithObject:login] animated:YES];
self.window.rootViewController=controller;

我使用简单的方法：

UIStoryboard *sb = [UIStoryboard storyboardWithName:@"NameOfStoryBoard" bundle:nil];
UITabBarController *rootViewController = [sb instantiateViewControllerWithIdentifier:@"NameOfTabBarController"];
[[UIApplication sharedApplication].keyWindow setRootViewController:rootViewController];

在swift中，我们可以按如下方式实施

let storyboard = UIStoryboard(name: "StartingPage", bundle: NSBundle.mainBundle())      
let loginView: SignInVC = storyboard.instantiateViewControllerWithIdentifier("SignInVC") as! SignInVC
UIApplication.sharedApplication().keyWindow?.rootViewController = loginView

为了补充Sunny Shah的答案，这是它的Swift 3版本：

        let mainStoryBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
        let viewController: UIViewController = mainStoryBoard.instantiateViewController(withIdentifier: "MainTabBarController") as! UITabBarController
        UIApplication.shared.keyWindow?.rootViewController = viewController

Swift 3代码：

在didFinishLaunchingWithOptions Appdelegate函数中使用以下内容。
将“HomeViewController”替换为要在应用程序启动时设置为根ViewController的ViewController

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

let storyboard = UIStoryboard(name: "Main", bundle: nil)

let initialViewController = storyboard.instantiateViewController(withIdentifier: "HomeViewController")

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

return true

目标c

步骤1：从info.plist中删除主故事板

步骤2：在界面生成器中将情节提要id添加到视图控制器

步骤3：将以下代码添加到app delegate中的application did finish方法

self.window = [[UIWindow alloc] initWithFrame: [UIScreen mainScreen].bounds];


//set main story board
if( condition){
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"StoryboardName1" bundle:nil];
    UIViewController *rootViewController = [storyboard instantiateViewControllerWithIdentifier:@"ViewController1"];
    [[UIApplication sharedApplication].keyWindow setRootViewController:rootViewController];
    [self window].rootViewController = rootViewController;
    [self.window makeKeyAndVisible];
}else{
    UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"StoryboardName2" bundle:nil];
    UIViewController *rootViewController = [storyboard instantiateViewControllerWithIdentifier:@"ViewController2"];
    [[UIApplication sharedApplication].keyWindow setRootViewController:rootViewController];
    [self window].rootViewController = rootViewController;
    [self.window makeKeyAndVisible];
}

这是一篇旧文章，但我会回复。
我不建议使用以下代码

let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
UIApplication.shared.keyWindow?.rootViewController = viewController

因为您正在创建两个实例。
我建议在适当的ViewController中编写以下代码

let appDelegate = UIApplication.shared.delegate as! AppDelegate
appDelegate.window?.rootViewController = self

Swift 5+Xcode 11:

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
UIApplication.shared.windows.first?.rootViewController = viewController
UIApplication.shared.windows.first?.makeKeyAndVisible()

这样做：

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
self.view.window?.rootViewController = viewController
self.view.window?.makeKeyAndVisible()

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
UIApplication.shared.windows.first?.rootViewController = viewController
UIApplication.shared.windows.first?.makeKeyAndVisible()

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
self.view.window?.rootViewController = viewController
self.view.window?.makeKeyAndVisible()

或者像这样：

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
self.view.window?.rootViewController = viewController
self.view.window?.makeKeyAndVisible()

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
UIApplication.shared.windows.first?.rootViewController = viewController
UIApplication.shared.windows.first?.makeKeyAndVisible()

let viewController = mainStoryboard.instantiateViewController(withIdentifier: "tabBarcontroller") as! UITabBarController
self.view.window?.rootViewController = viewController
self.view.window?.makeKeyAndVisible()

两者都很好
 那么，从plist文件中删除情节提要并取消选中IntalViewController如何。另外，newRootVC不在故事板中。没有故事板将在那里您的根视图控制器将被更改Hello，现在在应用程序启动时，我将我的productTour VC作为rootVC，现在当用户退出productTour时，我想再次将我的根VC移到TabBar，如何操作我已经编辑了代码并提交了编辑。我正在我的应用程序中使用它。只想注意，在
使用选项完成启动期间，
应用程序还没有设置keyWindow，所以你应该使用
self.window.rootViewController=…
在这种情况下，与我的问题中的上述情况相同…请检查Hello@Mayank，你收到了吗。伙计们，对不起，应用程序BecomeActive中有一些代码导致了此问题，现在问题已经解决。谢谢大家，你说得对。您好，现在在应用程序启动时，我让我的productTour VC作为根VC，现在当用户退出productTour时，我想再次将我的根VC转移到TabBar，如何做到这一点？此代码段与公认的答案有何不同？谢谢您的想法。这对我很有用：
func应用程序（application:UIApplication，didFinishLaunchwithOptions launchOptions:[uiApplicationLaunchOptions:Any]？）->Bool{if ProcessInfo.ProcessInfo.arguments.contains（“xuitests”）{window？.layer.speed=100.0//在模拟器中加速测试大约3x}返回true}