以编程方式更改storyBoard的rootViewController

Question

我使用Storyboards创建了我的项目。根ViewController位于Storyboard内，我没有在appDelegate写一个代码。

现在我想展示我的应用程序，所以我想将ViewController的根Tab Bar更改为我的TourVC，当应用程序的浏览完成后，我想再次将我的根ViewController切换回Tab Bar。

所以我在网上查询并遵循以下几点

1）从app.plist文件中删除Storyboards，2）从Storyboards取消选中“isInitialViewController”选项，在Tab Bar控制器的情况下检查它，因为它的根ViewController，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;

但我的应用程序崩溃与此错误日志，

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

我也收到警告，

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

Answer 1

Objective-C的：

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;

斯威夫特3：

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

Answer 2

在主故事板中为您的班级设置故事板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;

Answer 3

在swift中我们可以实现如下

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

Answer 4

我用这个简单：

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

Answer 5

只是为了添加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

Answer 6

这是一篇旧文章，但我会回复。我不推荐以下代码。

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

Answer 7

Swift 3代码：

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

Answer 8

目标c

第1步：从info.plist中删除主要故事板

步骤2：在界面构建器中将storyboard id添加到视图控制器

第3步：将以下代码添加到应用程序中，在app委托中完成方法

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];
}