Swift Storyboard app launches to a black screen

Question

Hi everyone,

I'm building a Swift app using Storyboards. I've been working fine for a few months now, but all of a sudden my app won't load properly. Whenever I open it on a Simulator or my physical iPhone, the launch screen is displayed before a black screen appears.

My Mac is on macOS Big Sur Developer Beta 5 with Xcode 12 Beta 6, and my iPhone is on iOS 14 Developer Beta 5.

This happened all of a sudden and I don't recall doing anything to cause it.

Here's what I've tried so far...

Renaming the storyboard and updating the target's General tab to the new name, as well as doing the same but manually editing Info.plist
Moving the storyboard in and out of "Copy Bundle Resources"
Updating to the latest Xcode 12 beta (I'm on macOS Big Sur)
Clearing Derived Data with DevCleaner
Starting a whole new project and moving all of my code and resources over via drag-and-drop (Interesting observation: when I started a new project, I added a simple label to the default Main.storyboard and ran it on my iPhone. The label wasn't displayed.
Adding a function to my AppDelegate to load the storyboard manually on launch
Adding various print statements in AppDelegate and my Home View Controller

AppDelegate

I've added

Code Block swiftlet storyboard = UIStoryboard(name: "Main", bundle: nil)
let initialViewController = storyboard.instantiateViewController(withIdentifier: "Home")
self.window.rootViewController = initialViewController
self.window.makeKeyAndVisible()
print("App launched")

to my AppDelegate. Now, when I run my app, I get
printed. I also added

Code Block swiftoverride func viewDidLoad() {
	super.viewDidLoad()
	print("Home view loaded")

to my Home View Controller.
Now, when I run my app, I get this printed in Xcode:

Code Block text2020-08-28 13:11:20.140963+0100 MY-APP[11077:1951343] libMobileGestalt MobileGestaltCache.c:166: Cache loaded with 4536 pre-cached in CacheData and 53 items in CacheExtra.
2020-08-28 13:11:20.759943+0100 MY-APP[11077:1951162] Metal API Validation Enabled
Home view loaded
App launched

Still, nothing on my iPhone. The launch screen appears, fades to black, and that's it. I'm so confused.

If anyone knows how to fix this, or something I can try, please let me know. Thank you in advance!

2.2k

Posted by

NoahEvans

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Answer 1

Have you a scene delegate ? You should.

Posted by

Claude31

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Answer 2

I do:

Code Block Swiftimport UIKit
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
    var window: UIWindow?
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
        guard let _ = (scene as? UIWindowScene) else { return }
    }
    func sceneDidDisconnect(_ scene: UIScene) {
    }
    func sceneDidBecomeActive(_ scene: UIScene) {
    }
    func sceneWillResignActive(_ scene: UIScene) {
    }
    func sceneWillEnterForeground(_ scene: UIScene) {
    }
    func sceneDidEnterBackground(_ scene: UIScene) {
    }
}

Thanks for your help.

Posted by

NoahEvans

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Answer 3

New try.

Did you remove the declaration

Code Block     var window: UIWindow?

from AppDelegate ?

Posted by

Claude31

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Answer 4

I did have that removed for some reason, but even after adding it my app still launches to a black screen.

To clarify, here's my AppDelegate:

Code Block Swiftimport UIKit
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?
   func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
      return true
    }
    func application(_ application: UIApplication, configurationForConnecting connectingSceneSession: UISceneSession, options: UIScene.ConnectionOptions) -> UISceneConfiguration {
        return UISceneConfiguration(name: "Default Configuration", sessionRole: connectingSceneSession.role)
    }
    func application(_ application: UIApplication, didDiscardSceneSessions sceneSessions: Set<UISceneSession>) {
    }    
    func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
        print(url)
        return true
    }
}

And here's my SceneDelegate:

Code Block Swiftimport UIKit
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
    var window: UIWindow?
    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    }
    func sceneDidDisconnect(_ scene: UIScene) {
    }
    func sceneDidBecomeActive(_ scene: UIScene) {
    }
    func sceneWillResignActive(_ scene: UIScene) {
    }
    func sceneWillEnterForeground(_ scene: UIScene) {
    }
    func sceneDidEnterBackground(_ scene: UIScene) {
    }
}

Thanks again for your help.

Posted by

NoahEvans

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Answer 5

Check your info.plist

Have you an Application Scene Manifest ?

Here is what it looks like (I had to edit the url with a few spaces to remove)

Code Block <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http:  //www.apple.  com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<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>Main</string>
			</dict>
		</array>
	</dict>
</dict>
</plist>

Posted by

Claude31

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Answer 6

What is the deployment target? If it is iOS 12.4.8 or earlier, add this to the AppDelegate class:

Code Block swiftvar window: UIWindow?

Posted by

NSApps

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Answer 7

I have Xcode 12 beta 3 and I have never seen this issue!

Posted by

NSApps

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Swift Storyboard app launches to a black screen

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