Create apps that allow players to interact with each other using GameKit.

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GKLocalPlayer.authenticateHandler not called on iOS 26 when Game Center auth overlay is shown
Hi — we’re testing our app on iOS 26 and ran into strange behavior with GKLocalPlayer.local.authenticateHandler. GKLocalPlayer.local.authenticateHandler = { [weak self] viewController, error in // additional code } What happens: When we assign authenticateHandler on iOS 26 and the user is not signed in to Game Center, the system shows a full-screen Game Center overlay asking the user to sign in. If the user taps Cancel, nothing further happens — the closure is not invoked again, so we don’t receive an error or any callback. The app never learns whether the auth was cancelled or failed. In previous iOS versions the closure was called (with viewController / error as appropriate) and the flow worked as expected. What we tried: Verified authenticateHandler is being set. Checked GKLocalPlayer.local.isAuthenticated after the overlay dismisses — it’s unchanged. Observed system logs: a com.apple.GameOverlayUI scene is created and later removed (so the auth overlay is shown by the system). Confirmed the same code works on earlier iOS versions. :thinking: Question: Has anyone seen authenticateHandler not being invoked on iOS 26 when the Game Center auth overlay is presented? Could this be a behavioral change in iOS 26 (overlay runs in a separate system process), or a bug? Any suggested workarounds to reliably detect that the user cancelled the sign-in (for example: listening for willResignActive / didBecomeActive, watching for a system overlay, or saving/presenting the viewController manually)? Thanks in advance for any advice — we’d appreciate pointers or suggested diagnostics ?
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GameplayKit usage with Swift 6: Call to main actor-isolated instance method 'run' in a synchronous nonisolated context
Hi there, With a couple of other developers we have been busy with migrating our SpriteKit games and frameworks to Swift 6. There is one issue we are unable to resolve, and this involves the interaction between SpriteKit and GameplayKit. There is a very small demo repo created that clearly demonstrates the issue. It can be found here: https://github.com/AchrafKassioui/GameplayKitExplorer/blob/main/GameplayKitExplorer/Basic.swift The relevant code also pasted here: import SwiftUI import SpriteKit struct BasicView: View { var body: some View { SpriteView(scene: BasicScene()) .ignoresSafeArea() } } #Preview { BasicView() } class BasicScene: SKScene { override func didMove(to view: SKView) { size = view.bounds.size anchorPoint = CGPoint(x: 0.5, y: 0.5) backgroundColor = .gray view.isMultipleTouchEnabled = true let entity = BasicEntity(color: .systemYellow, size: CGSize(width: 100, height: 100)) if let renderComponent = entity.component(ofType: BasicRenderComponent.self) { addChild(renderComponent.sprite) } } } @MainActor class BasicEntity: GKEntity { init(color: SKColor, size: CGSize) { super.init() let renderComponent = BasicRenderComponent(color: color, size: size) addComponent(renderComponent) let animationComponent = BasicAnimationComponent() addComponent(animationComponent) } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } } @MainActor class BasicRenderComponent: GKComponent { let sprite: SKSpriteNode init(color: SKColor, size: CGSize) { self.sprite = SKSpriteNode(texture: nil, color: color, size: size) super.init() } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } } class BasicAnimationComponent: GKComponent { let action1 = SKAction.scale(to: 1.3, duration: 0.07) let action2 = SKAction.scale(to: 1, duration: 0.15) override init() { super.init() } override func didAddToEntity() { if let renderComponent = entity?.component(ofType: BasicRenderComponent.self) { renderComponent.sprite.run(SKAction.repeatForever(SKAction.sequence([action1, action2]))) } } required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") } } As SKNode is designed to run on the MainActor, the BasicRenderComponent is attributed with MainActor as well. This is needed as this GKComponent is dedicated to encapsulate the node that is rendered to the scene. There is also a BasicAnimationComponent, this GKComponent is responsible for animating the rendered node. Obviously, this is just an example, but when using GameplayKit in combination with SpriteKit it is very common that a GKComponent instance manipulates an SKNode referenced from another GKComponent instance, often done via open func update(deltaTime seconds: TimeInterval) or as in this example, inside didAddToEntity. Now, the problem is that in the above example (but the same goes foupdate(deltaTime seconds: TimeInterval) the methoddidAddToEntity is not isolated to the MainActor, as GKComponent is not either. This leads to the error Call to main actor-isolated instance method 'run' in a synchronous nonisolated context, as indeed the compiler can not infer that didAddToEntity is isolated to the MainActor. Marking BasicAnimationComponent as @MainActor does not help, as this isolation is not propogated back to the superclass inherited methods. In fact, we tried a plethora of other options, but none resolved this issue. How should we proceed with this? As of now, this is really holding us back migrating to Swift 6. Hope someone is able to help out here!
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Oct ’24
GameKit Access Point causes camera background image in ARKit to be black in iOS 18 beta only
I have an AR game using ARKit with SceneKit that works just fine in iOS 17. In the iOS 18 betas, the AR background image shows black instead of showing the real world. As a result there's no tracking and obviously the whole game is useless. I narrowed down the issue to showing the Game Center Access Point. My app has ViewController 1 (VC1) showing the main menu and that's where I want to show the GC Access Point. From there you open VC2 which shows a list of levels. Selecting any level will open VC3 which has the ARScene. Following is the code I use to start Game Center in VC1: GKLocalPlayer.local.authenticateHandler = { gcAuthVC, error in let isGameCenterReady = (gcAuthVC == nil) && (error == nil) if let viewController = gcAuthVC { self.present (viewController, animated: true, completion: nil) } if error != nil { print(error?.localizedDescription ?? "") } if isGameCenterReady { GKAccessPoint.shared.location = .topLeading GKAccessPoint.shared.showHighlights = true GKAccessPoint.shared.isActive = true } } When switching to VC2 I run GKAccessPoint.shared.isActive = false so that the Access Point will no longer show in any of the following VCs. I tried running it in VC1, VC2, and again in VC3 - it doesn't change anything. Once I reach VC3, the background is black. If in VC1 I don't run GKAccessPoint.shared.isActive = true, so I don't activate the access point, the behavior is as follows: If I wait until after the Game Center login animation completes and closes on its own and then I proceed to VC2 and VC3, the camera image will show correctly If I quickly move to VC2 before the Game Center login animation has completed, so my code will close it by setting active = false, and then I continue to VC3, I will see the black background problem. So it does look like activating the access point and then de-activating it causes the issue. BTW, if I activate the access point and leave it on in all VCs, the same black background issue persists. Other than that, when I'm in VC3 with the black background and I switch to another app (so my game moves to the background), when it returns to the foreground, the camera suddenly shows the real world correctly! I tried to manually reset the AR session by pausing and restarting it, but that didn't change anything. Also, when I check with the debugger, it looks like when the app comes back to the foreground it also doesn't run the session start code. But something does seem to reset itself so I wonder what that is. Maybe I could trigger the same manually in my cdoe??? I repeat that everything works just fine in iOS 17 and below. This problem only started with the iOS 18 beta (currently on beta 5, but it started in some of the previous betas as well). So could this be a bug in iOS 18? As a workaround I could check the iOS version and if it's iOS18 not activate the access point, hoping that the user will not jump to VC2 too quickly, and show my own button which will open Game Center. But I'd rather give the users the full experience with their own avatar and the highlights showing up. Plus, certainly some users will move quickly to VC2 and that will be an awful experience. Any help would be greatly appreciated. Thanks!
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Mar ’25
GameKit not working as expected in iOS 26.
I just upgraded my macOS, Xcode and Simulator all to the newest beta version 26. Then I found two issues when building my app with Xcode 26 and running it on simulator 26. The game center access point no longer shows up in the app. This is how it's configured in the past. And it still works on simulator 18.4 func authenticatePlayer() { GKAccessPoint.shared.location = .topTrailing self.localPlayer.authenticateHandler = { viewController, error in if let viewController = viewController { // can present Game Center login screen } else if self.localPlayer.isAuthenticated { // game can be started } else { // user didn't log in, continue the game without game center } } } After game ended, the leaderboard won't load. This is how it's implemented in the past. It's still working in simulator 18.4 struct GameCenterView: UIViewControllerRepresentable { @Environment(\.presentationMode) var presentationMode ... func makeUIViewController(context: Context) -> GKGameCenterViewController { let viewController = GKGameCenterViewController( leaderboardID: getLeaderBoardID(with: leaderBoardGameMode), playerScope: .global, timeScope: .allTime ) viewController.gameCenterDelegate = context.coordinator return viewController } func updateUIViewController(_ uiViewController: GKGameCenterViewController, context: Context) {} func makeCoordinator() -> Coordinator { Coordinator(self) } class Coordinator: NSObject, GKGameCenterControllerDelegate { let parent: GameCenterView init(_ parent: GameCenterView) { self.parent = parent } func gameCenterViewControllerDidFinish(_ gameCenterViewController: GKGameCenterViewController) { parent.presentationMode.wrappedValue.dismiss() } } }
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GKLocalPlayer save and fetch data to iCloud issue
Hi all I have two mystic issues with saving and fetching data to and from iCloud. Both repro only after first launch of an app. 1. [GKLocalPlayer fetchSavedGamesWithCompletionHandler:] After first attempt I can see 0 saved games (but i know that there is at least one saved game) and there is no any error. In case if I try fetch one more time (without any additional actions) even immediately after first attempt I receive saved games correctly (not 0) 2. [GKLocalPlayer saveGameData: withName: completionHandler:] After first attempt I can see error The requested operation could not be completed because local player has not been authenticated. In case if I try save one more time (without any additional actions) even immediately after first attempt I can save data successfully without any error I found the same issue in StackOverflow, but there are no fixes...
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1.4k
Feb ’25
Error "No Apple native plug-in libraries found." when importing freshly built plugins into Unity
I just built Core and GameKit without errors. The command line I used was the following: python3 build.py -p Core GameKit -m macOS -c "Apple Development ID (redacted)" When importing these packages into Unity, as soon as the editor refreshes I get these errors: DllNotFoundException: GameKitWrapper assembly:<unknown assembly> type:<unknown type> member:(null) And DllNotFoundException: AppleCoreNativeMac assembly:<unknown assembly> type:<unknown type> member:(null) And Apple Unity Plug-ins] No Apple native plug-in libraries found. Were the libraries built with the build script (build.py), xcodebuild, or Xcode? Was any output generated from the build script/tool? Were there any errors or issues? Please check to ensure that libraries (.a, .framework, or .bundle files) were created and saved to each plug-in's "NativeLibraries~" folder. I made sure that the libraries were saved to this NativeLibraries folder. I made sure to update xcode, python, npm and Unity to the latest version, got the most recent commity from Github (Sept. 17th) but the errors persist. The errors also occur right as the game starts in a built player. Also occurs in a blank Unity project, where I tested both 2022.3.17f and 2022.3.48f. The versions I was trying to import was Core 3.1.4 and GameKit 3.0.0. Same issue with Core 3.1.3 and Gamekit 2.2.2. Last version I tried that works was Core 1.05 and GameKit 1.04. I haven't seen anyone else encounter this on these forums so I'm guessing that I'm personally doing something wrong rather than there being an issue with the plugins themselves, but what am I doing wrong?
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Oct ’24
GKGameCenterViewController Is Blank On iOS 18
I'm displaying a GKGameCenterViewController after successfully authenticating and on iOS 18.0 and 18.1, I get a black screen. As a sanity check GKLocalPlayer.local.isAuthenticated is also returning true. The same code works just fine on iOS 17. Is there something that needs to be done on iOS 18 and above?
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Nov ’24
Crash after using Apply unity plugin (GameKit-3.0.0)
Hi, I tried to save the game progress using the official Apple plugin for Unity but the crash happened when I active the "iCloud Documents" inside capabilities and when deactivated it this error message appeared: Code=27 Domain=GKErrorDomain Description=The requested operation could not be completed because you are not signed in to iCloud or have not enabled iCloud Drive. (UbiquityContainerUnavailable) Authentication with Game Center works fine using the Core plugin, but nothing works correctly when I use the GameKit plugin. Note: I already active iCloud for app Identifier. Tichnecal informations: Unity version: 2022.3.47f1 LTS XCode 16 Swift 6 GameKit-3.0.0 (Apply unity plugin) Core-3.1.5 (Apply unity plugin)
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Nov ’24
Game Center Dashboard frequently not updating when new achievement unlocked
I am currently working on a game that involves earning achievements, which I am using the Apple Unity Plug-Ins to display. I have found that occasionally opening the Game Center Dashboard the last achievement earned will not be displayed until the game is closed and reopened. I am using GKAccessPoint.Shared.Trigger to display the Achievements screen, which occasionally seems to open a cached version of the dashboard. I've found that it seems to consistently happen when earning multiple achievements within one minute, but this is not always the case. Does anybody have any experience with something like this in the past?
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Feb ’25
Gamekit Achievements Won't Unhide
Added achievements to my approved app. Added them for the next release version, which I am running in simulator. When I look at the Achievements page, I can see that there are 17 Achievements available (correct), but they all show as hidden, despite checking the "No" box in App Store Connect.
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May ’25
How to Apple Unity Plugins
When running my game in the Unity Editor on Windows platform I get an error: DllNotFoundException: GameKitWrapper assembly:<unknown assembly> type:<unknown type> member:(null) Apple.GameKit.DefaultNSErrorHandler.Init () (at ./Library/PackageCache/com.apple.unityplugin.gamekit@0abcad546f73/Source/DefaultHandlers.cs:35) This is because GameKitWrapper dynamically linked library is not available under Windows platform. Besides, "Apple Build Settings" are declared under UNITY_EDITOR_OSX and also not available under Windows platform. Does anyone managed to solve this?
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Jul ’25
Blurry Game Center Achievement Images?
Hey all — I’ve been building out my first set of Game Center Achievements for a game I’m working on, and I’ve run into something odd with the image quality. The specs say to upload icons at 512x512 or 1024x1024@2x. I’ve been uploading 1024x1024 PNGs (without explicitly naming them “@2x” since there’s only one upload slot), assuming that Game Center would just handle the scaling automatically — kind of like how a lot of things are getting more streamlined across platforms lately. But in testing, the icons are showing up a bit blurry, especially in the Game Center interface. It’s not horrible, but it’s definitely softer than I expected — more like low-res than Retina. All my test devices (outside the Simulator) are running iOS 26, so I’m also wondering if this might be a beta-related display bug? Has anyone else run into this? Curious if I’m missing a best practice here, or if I really do need to ensure I’m uploading it with the @2x suffix, or maybe something else entirely? Thanks!
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Jul ’25
Issues building Unity plug-in project: Cannot locate native library Apple.Core/Apple.GameKit for iOS
I'm having issues getting a well built package from the Apple Unity Plug-in project. When building the my game project in Unity the following error is printed to the console: Apple.Core.AppleNativeLibraryUtility] Cannot locate a Debug or Release Apple.Core native library for iOS. Please ensure that the build invocation (build.py, xcodebuild, or Xcode) compiled cleanly and that the build was configured to support Debug on iOS. As far as I can tell the build did compile cleanly, but I might be missing something. If anyone can see what I'm doing wrong or has any insight it would be greatly appreciated. Setup is the following: macOS Tahoe 26 Beta Xcode-beta Version 26.0 beta 3 (17A5276g) Unity Plug-in branch: 2025-beta1 Unity game project version: 2022.3.60f M1 Macbook Pro The built packages have been imported into the game project through the Unity Package Manager using the tarball option pointing to the built packages from the Unity Plug-in project. The Unity Plug-in project has been built using the build.py file with the following: python3 build.py -m iOS iPhoneSimulator -p Core GameKit CoreHaptics GameController -k all The output is available in the attached file. build-output.txt Here's an image of the NativeLibraries~ folder inside the built Apple.Core package.
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Jul ’25
iOS 26 Games app: Wired Switch Pro controllers (and GameSir X5 Lite) not working correctly
Hi, Since iOS 26 introduced the new Games app, I’ve noticed a problem when using a Nintendo Switch Pro Controller in wired USB-C mode, and also with third-party controllers that emulate it (like the GameSir X5 Lite). In the Games app interface, only the L/R buttons respond, but the D-Pad and analog sticks don’t work at all. Once inside actual games, the controller works fine — the issue only affects the Games app UI. What I’ve tested so far: Xbox / PlayStation controllers → work fine in both wired and Bluetooth, including inside the Games app. Switch Pro Controller (Bluetooth) → works fine, including in the Games app. Switch Pro Controller (wired) → same issue as the X5 Lite, D-Pad and sticks don’t work in the Games app. This makes it hard to use the new Games app launcher with these controllers, even though they work perfectly once a game is launched. My question: is this an iOS bug (Apple needs to add proper support for wired Switch Pro controllers in the Games app), or something that Nintendo / GameSir would need to address? Thanks in advance to anyone who can confirm this or provide more info.
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Game Center challenges and activities issues for released game
We have a released game in the App Store with Game Center Challenges. The challenges were working well in testing of the final version before the Game Center challenges went live. After release the activity that should take the player to the challenge in game results in this printout and we do not get informed by GKGameActivityListener of the activity happening in our code as we did before the Game Center challenges went live. “Invalid game activity definition. Failed to kick activity notification to GameKit. Error: Error Domain=GKErrorDomain Code=17 "(null)"” Also, Game Center reports that the are no challenges in GKChallengeDefinition.all even though there are ongoing challenges. The leaderboard results do get reported to Game Center though and show up as challenge entries in the Games app. At the moment we are trying to figure out if this is a problem on our end or a Game Center server issue.
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Transferring Apps with iCloud KVS
Hi All! I'm being asked to migrate an app which utilizes iCloud KVS (Key Value Storage). This ability is a new-ish feature, and the documentation about this is sparse [1]. Honestly, the entire documentation about the new iCloud transfer functionality seems to be missing. Same with Game Center / GameKit. While the docs say that it should work, I'd like to understand the process in more detail. Has anyone migrated an iCloud KVS app? What happens after the transfer goes through, but before the first release? Do I need to do anything special? I see that the Entitlements file has the TeamID in the Key Value store - is that fine? <key>com.apple.developer.ubiquity-kvstore-identifier</key> <string>$(TeamIdentifierPrefix)$(CFBundleIdentifier)</string> Can someone please share their experience? Thank you! [1] https://developer.apple.com/help/app-store-connect/transfer-an-app/overview-of-app-transfer
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Feb ’25
Game Porting Toolkit Crashing Playing HighEnd Games
Updated to GPT 2 with the app format and whisky in October. I'm using steam in GPT to play the windows only games. The games consistently crash my computer to restart when I played games like Liar's Bar and Phasmophobia, the latter even with its performance optimization update released today. Both of them do that when I load into the game room, so the bar/ghost house or even while loading. It ran Outpath properly though, which was something with much lower quality than LB and Phas. I don't think it's a simple RAM config issue because Phasmophobia ran fine for me with older versions in GPT 1 although I did experience occasional crashes but I think those were only crashing the game not my mac. I'm not sure what I'm doing wrong that I can't run those games or if it's a GPT problem. I'm using a MPB Pro M1 with 16GB memory on Sequoia 15.0.1.
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Oct ’24
GKGameCenterViewController won't turn off.
GKGameCenterViewController won't turn off. With Core and GameKit from GitHub apple/unityplugins, I succeeded in logging in and displaying GKGameCenterViewController. Other leaderboards and everything work fine, but when I press X on GameCenter to return to the game, nothing happens. I tried debugging by printing logs here and there in the plugin to check, but I didn't get any results. When I press X, I couldn't get any logs or responses. It was like a button with no listener attached. No, it was more like an image. Based on the community posts that said it worked fine before, it seems that the recent GameCenter update was not applied to the plugin, was omitted, or changed, causing a mismatch.
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Nov ’24
Unable to test Game Center achievements in ad hoc builds to registered device
Hi, I have a test app with a single "game centre achievement" and I am running it on my iPad and unable to list that achievement with GameCenterManager.shared.loadAchievements The app is still in version 1.0, prepare for submission status, (it is not ready for review submission). Game Center entitlement is added for the app and the achievement is added to the Game Center section of app. However it is marked as NotLive. I am using a sandbox account to login to game centre on the iPad and I can't fetch this achievement. Is it because it is "NotLive". ? How do I test my Game Center achivement on the device without releasing it yet.
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Nov ’24