未能实例化 UIMainStoryboardFile‘ Main’的默认视图控制器-也许指定的入口点没有设置？

我在一个新创建的应用程序中使用 Xcode，当我运行这个项目时，它并没有显示在 iOS 模拟器中，我得到了以下信息:

未能实例化 UIMainStoryboardFile‘ Main’的默认视图控制器-也许指定的入口点没有设置？

当然，我已经在 Google 上搜索过了，每个人都指出这是因为 Xcode 还不知道哪个视图控制器是最初的控制器。但奇怪的是，我创建了一个基于页面的应用程序(也尝试了单视图和选项卡应用程序选项) ，Xcode 已经为它定义了一个故事板。

此外，当我转到项目的主界面选项时，故事板(Xcode 自己命名为“ Main”)被设置，在故事板中，我的视图控制器被设置为“ InitialView 控制器”

Is Initial View Controller

怎么了？

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Setup the window manually,

- (void)applicationDidBecomeActive:(UIApplication *)application
{
if (!application.keyWindow.rootViewController)
{
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle:nil];


UIViewController *myViewController= [storyboard instantiateViewControllerWithIdentifier:@"myViewController identifier"];


application.keyWindow.rootViewController = myViewController;
}
}
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最佳答案

So this also happened to me too. I checked 50 times and my "Is Initial View Controller" was checked, believe me. It happened out of the blue. So how did I fix it?

  1. Create a new Storyboard in your project, name it something like Main_iPhoneV2 (or iPadV2 depending on your original storyboard style)
  2. Open the broken storyboard, click anywhere in the white area and press command-a, then command-c (select all and copy)
  3. Open your new storyboard and press command-v to paste the same exact setup
  4. Go to your project settings, change your "Main Interface" to the new Main_iPhoneV2 (If it's your iPad and you're writing a universal app, you'll have to edit the -Info.plist and look for the value "Main storyboard file base name (iPad)
  5. Recompile, and stop pulling your hair out
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Check Is Initial View Controller in the Attributes Inspector.

enter image description here

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First click on the View Controller in the right hand side Utilities bar. Next select the Attributes Inspector and make sure that under the View Controller section the 'Is Initial View Controller' checkbox is checked!

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Product "Clean" was the solution for me.

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If you have been committing your code to source control regularly, this may save you the hassle of creating a new Storyboard and possibly introducing more problems...

I was able to solve this by comparing the Git source code of the version that worked against the broken one. The diff showed that the first line should contain the Id of the initial view controller, in my case, initialViewController="Q7U-eo-vxw". I searched through the source code to be sure that the id existed. All I had to do was put it back and everything worked again!

<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="5056" systemVersion="13E28" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" initialViewController="Q7U-eo-vxw">
<dependencies>
<deployment defaultVersion="1296" identifier="iOS"/>
<plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="3733"/>
</dependencies>
<scenes>

Here are some steps that can help you troubleshoot:

  1. Right click the failing Storyboard and use Source Control > Commit... to preserve your changes since the last commit.
  2. Try right clicking your failing Storyboard and use "Open As > Source Code" to view the XML of the storyboard.
  3. In the document element, look for the attribute named "initialViewController". If it is missing, don't worry, we'll fix that. If it is there, double click the id that is assigned to it, command-c to copy it, command-f command-v to search for it deeper in the document. This is the identifier of the controller that should provide the initial view. If it is not defined in the document then that is a problem - you should remove it from the document tag, in my case initialViewController="Q7U-eo-vxw".
  4. Go to Xcode menu item called View and choose Version Editor > Show Comparison View
  5. This shows your local version on the left and the historical version on the right. Click on the date beneath the historical version to get a list of the commits for this story board. Choose one that you know worked and compare the document element. What is the id of the *initialViewController? Is it different? If so, try editing it back in by hand and running. xcode historical compare tool in action
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I get this error when I change the the storyboard file name "Main.storyboard" TO: "XXX.storyboard"

The solution for me was:

  • Product->Clean
  • CHANGE: Supporting Files -> info.plist -> Main storyboard file base name -> Main TO: XXX

Good Luck

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Using Interface Builder :

Check if 'Is initial view controller' is set. You can set it using below steps :

  1. Select your view controller (which is to be appeared as initial screen).
  2. Select Attribute inspector from Utilities window.
  3. Select 'Is Initial View Controller' from View Controller section (if not).

If you have done this step and still getting error then uncheck and do it again.

Steps to solve problem

Using programmatically :

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;

Swift :

        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
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This warning is also reported if you have some code like:

window = UIWindow(frame: UIScreen.mainScreen().bounds)
window?.rootViewController = myAwesomeRootViewController
window?.makeKeyAndVisible()

In this case, go to Target > General > Deployment Info and set Main Interface to empty, since you don't need a storyboard entry for your app:

empty Main Interface

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If you added new storyboard then you have to check following points:

  1. In your plist file check value of Main storyboard file base name (iPad) or (iPhone) should be matched with your storyboard file name (do not add extension .storyboard)

  2. In storyboard there should be one view controller which set as Is initial view controller

  3. Clean and build your project. :)

enter image description here

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Apart from above correct answer, also make sure that you have set correct Main Interface in General.

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I have experienced this with my Tab Bar Controller not appearing in the Simulator along with a black screen. I did the following in order for my app to appear in the Simulator.

  1. Go to Main.storyboard.
  2. Check the Is Initial View Controller under the Attributes inspector tab.

Is Initial View Controller in the Attributes Inspector.

If you accidentally deleted that view controller, or otherwise made it not the default, then you’ll see the error “Failed to instantiate the default view controller for UIMainStoryboardFile 'Main' - perhaps the designated entry point is not set?” when your app launches, along with a plain black screen.

To fix the problem, open your Main.storyboard file and find whichever view controller you want to be shown when your app first runs. When it’s selected, go to the attributes inspector and check the box marked “Is Initial View Controller”. You should see a right-facing arrow appear to the left of that view controller, showing that it’s your storyboard’s entry point.

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Check if you have the window var in the AppDelegate. 

var window: UIWindow?

And also check the storyboard of your Info.plist file. 

<key>UIMainStoryboardFile</key>
<string>Main</string>

Programmatically setting the rootViewController in the AppDelegate is not going to fix the warning. You should choose whether to let to the storyboard set the view controller or do it programmatically.

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1st option

if you want to set your custom storyboard instead of a default view controller.

Change this attribute from info.plist file

<key>UISceneStoryboardFile</key> <string>Onboarding</string>

Onboarding would be your storyboard name

to open this right-click on info.plist file and open as a source code

2nd option

1- Click on your project

2- Select your project from the target section

3- Move to Deployment interface section

4- Change your storyboard section from Main Interface field

Please remember set your storyboard initial view controller

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Projects created in Xcode 11 and above, simply changing the Main Interface file from the project settings won't be enough.

You have to manually edit the Info.plist file and set the storyboard name for the UISceneStoryboardFile as well.

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None of the above solved the issue for me. In my case it was not also setting the correct application scene manifest.

I had to change LoginScreen used to be Main

enter image description here

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If you have scene delegate you have to check in info.plist

<key>UIApplicationSceneManifest</key>
<dict>
<key>UIApplicationSupportsMultipleScenes</key>
<false/>
<key>UISceneConfigurations</key>
<dict>
<key>UIWindowSceneSessionRoleApplication</key>
<array>
<dict>
<key>UISceneConfigurationName</key>
<string>Default Configuration</string>
<key>UISceneDelegateClassName</key>
<string>$(PRODUCT_MODULE_NAME).SceneDelegate</string>
<key>UISceneStoryboardFile</key>
<string>Login</string>
</dict>
</array>
</dict>
</dict>

I'm here loading my storyboard called Login.storyboard

plist

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If you've created a new Storyboard with a name other than "Main" there will be some problems, but it's easy to adjust...

So after you've created a new Storyboard with the desired name and you want to use it as the main story, do the following:

  1. Check box 'Is Initial View Controller' inside Attributes Inspector: 1
  2. Choose desired storyboard as 'Main Interface' for your target: 2
  3. Open project Info.plist and find a property 'Storyboard Name' where you should type your desired Storyboard name as value 3
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What worked for me in XCode 14.0.1 was, apart from setting initial view controller, to update in Build Settings: "UIKIT Main Storyboard File Base Name" to new the name of new storyboard

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If you are not using storyboard

Open info.plist In the info.plist file delete the following feature Information Property List -> Scene configuration -> Application Session Role -> Item 0 -> StoryBoard Name


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