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

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Game Center Authentication Crashing - Unity 6, Gamekit 3.0.2
When testing my development build for gamecenter authentication, the game crashes. I've breadcrumbed it to the "await GKLocalPlayer.Authenticate();" call. Can't find any documentation on this issue and have been looking through the forums! I've already done all of the usual stuff like verifying bundle identifiers match, ensuring game center is enabled for the app, setting up app store connect, using a sandbox account, etc... Please point me to some resources if you know any. Any help is appreciated, I'm starting to lose hope here!
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100
Apr ’25
Matchmaking issue on tvOS with GKMatchmakerViewController
Hello, We are working on a real-time 2-player online game targeting multiple Apple devices. The following issue only occurs on tvOS: When selecting matchmaking to connect with another player, the native Game Center interface opens and begins the matchmaking process. Almost immediately, the following log appears in the console, and the matchmaking screen remains indefinitely without completing: Timeout while starting matching with request: <GKMatchRequestInternal 0x30d62f690> { defaultNumberOfPlayers : 0 isLateJoin : 0 localPlayerID : U:bea182d69b85f0839e3958742fbc4609 matchType : 0 maxPlayers : 2 minPlayers : 2 playerAttributes : 4294967295 playerGroup : 1 preloadedMatch : 0 recipientPlayerIDs : <__NSArrayM 0x3034ed5c0> {} recipients : <__NSArrayM 0x3034ee280> {} restrictToAutomatch : 0 version : 1 archivedSharePlayInviteeTokensFromProgrammaticInvite, inviteMessage, localizableInviteMessage, messagesBasedRecipients, properties, queueName, recipientProperties, rid, sessionToken : (null) } . Error: (null) However, the task does not complete when the log appears (our Debug.Log are nerver called). But if we manually cancel the matchmaking process, the "User cancel" log is correctly triggered. Here is a code snippet for the request : var gkMatchRequest = GKMatchRequest.Init(); gkMatchRequest.MinPlayers = 2; gkMatchRequest.MaxPlayers = 2; var matchRequestTask = GKMatchmakerViewController.Request(gkMatchRequest); matchRequestTask.ContinueWith(t => { Debug.LogException(t.Exception); }, TaskContinuationOptions.OnlyOnFaulted); matchRequestTask.ContinueWith(t => { Debug.LogInfo("User cancel"); }, TaskContinuationOptions.OnlyOnCanceled); matchRequestTask.ContinueWith(t => { Debug.LogInfo("Success"); }, TaskContinuationOptions.OnlyOnRanToCompletion); We have tested this on multiple devices and network types (Wi-Fi, 5G, Ethernet), but we consistently encounter this bug along with the same log message. Could you please help us understand or resolve this issue? Thank you.
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Apr ’25
Matchmaking issue on tvOS with GKMatchmakerViewController.Request
Hello ! We are working on a real-time 2-player online game targeting multiple Apple devices. The following issue only occurs on tvOS: When selecting matchmaking to connect with another random player, the native Game Center interface opens and begins the matchmaking process. Almost immediately after clicking "start", the following log appears in the console, and the matchmaking screen remains indefinitely without completing: Timeout while starting matching with request: <GKMatchRequestInternal 0x30d62f690> { defaultNumberOfPlayers : 0 isLateJoin : 0 localPlayerID : U:bea182d69b85f0839e3958742fbc4609 matchType : 0 maxPlayers : 2 minPlayers : 2 playerAttributes : 4294967295 playerGroup : 1 preloadedMatch : 0 recipientPlayerIDs : <__NSArrayM 0x3034ed5c0> {} recipients : <__NSArrayM 0x3034ee280> {} restrictToAutomatch : 0 version : 1 archivedSharePlayInviteeTokensFromProgrammaticInvite, inviteMessage, localizableInviteMessage, messagesBasedRecipients, properties, queueName, recipientProperties, rid, sessionToken : (null) } . Error: (null) However, as shown in the code snippet below, the task does not complete when the log appears. But when we manually cancel the matchmaking process, the "User cancel" log is correctly triggered. var gkMatchRequest = GKMatchRequest.Init(); gkMatchRequest.MinPlayers = 2; gkMatchRequest.MaxPlayers = 2; var matchRequestTask = GKMatchmakerViewController.Request(gkMatchRequest); matchRequestTask.ContinueWith(t => { Debug.LogException(t.Exception); }, TaskContinuationOptions.OnlyOnFaulted); matchRequestTask.ContinueWith(t => { Debug.Log("User cancel"); }, TaskContinuationOptions.OnlyOnCanceled); matchRequestTask.ContinueWith(t => { Debug.Log("Success"); }, TaskContinuationOptions.OnlyOnRanToCompletion); We have tested this on multiple Apple TV and network types (Wi-Fi, 5G, Ethernet), but we consistently encounter this bug along with the same log message. Could you please help us understand or resolve this issue? Thank you.
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Apr ’25
GKMatch.chooseBestHostingPlayer(_:) always returns nil player
I'm building a game with a client-server architecture. Using GKMatch.chooseBestHostingPlayer(_:) rarely works. When I started testing it today, it worked once at the very beginning, and since then it always succeeds on one client and returns nil on the other client. I'm testing with a Mac and an iPhone. Sometimes it fails on the Mac, sometimes on the iPhone. On the device that it succeeds on, the provided host can be the device itself or the other one. I created FB9583628 in August 2021, but after the Feedback Assistant team replied that they are not able to reproduce it, the feedback never went forward. import SceneKit import GameKit #if os(macOS) typealias ViewController = NSViewController #else typealias ViewController = UIViewController #endif class GameViewController: ViewController, GKMatchmakerViewControllerDelegate, GKMatchDelegate { var match: GKMatch? var matchStarted = false override func viewDidLoad() { super.viewDidLoad() GKLocalPlayer.local.authenticateHandler = authenticate } private func authenticate(_ viewController: ViewController?, _ error: Error?) { #if os(macOS) if let viewController = viewController { presentAsSheet(viewController) } else if let error = error { print(error) } else { print("authenticated as \(GKLocalPlayer.local.gamePlayerID)") let viewController = GKMatchmakerViewController(matchRequest: defaultMatchRequest())! viewController.matchmakerDelegate = self GKDialogController.shared().present(viewController) } #else if let viewController = viewController { present(viewController, animated: true) } else if let error = error { print(error) } else { print("authenticated as \(GKLocalPlayer.local.gamePlayerID)") let viewController = GKMatchmakerViewController(matchRequest: defaultMatchRequest())! viewController.matchmakerDelegate = self present(viewController, animated: true) } #endif } private func defaultMatchRequest() -> GKMatchRequest { let request = GKMatchRequest() request.minPlayers = 2 request.maxPlayers = 2 request.defaultNumberOfPlayers = 2 request.inviteMessage = "Ciao!" return request } func matchmakerViewControllerWasCancelled(_ viewController: GKMatchmakerViewController) { print("cancelled") } func matchmakerViewController(_ viewController: GKMatchmakerViewController, didFailWithError error: Error) { print(error) } func matchmakerViewController(_ viewController: GKMatchmakerViewController, didFind match: GKMatch) { self.match = match match.delegate = self startMatch() } func match(_ match: GKMatch, player: GKPlayer, didChange state: GKPlayerConnectionState) { print("\(player.gamePlayerID) changed state to \(String(describing: state))") startMatch() } func startMatch() { let match = match! if matchStarted || match.expectedPlayerCount > 0 { return } print("starting match with local player \(GKLocalPlayer.local.gamePlayerID) and remote players \(match.players.map({ $0.gamePlayerID }))") match.chooseBestHostingPlayer { host in print("host is \(String(describing: host?.gamePlayerID))") } } }
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Apr ’25
How to get GKMatch instance after accepting GKInvite?
In my SceneKit game I'm able to connect two players with GKMatchmakerViewController. Now I want to support the scenario where one of them disconnects and wants to reconnect. I tried to do this with this code: nonisolated public func match(_ match: GKMatch, player: GKPlayer, didChange state: GKPlayerConnectionState) { Task { @MainActor in switch state { case .connected: break case .disconnected, .unknown: let matchRequest = GKMatchRequest() matchRequest.recipients = [player] do { try await GKMatchmaker.shared().addPlayers(to: match, matchRequest: matchRequest) } catch { } @unknown default: break } } } nonisolated public func player(_ player: GKPlayer, didAccept invite: GKInvite) { guard let viewController = GKMatchmakerViewController(invite: invite) else { return } viewController.matchmakerDelegate = self present(viewController) } But after presenting the view controller with GKMatchmakerViewController(invite:), nothing else happens. I would expect matchmakerViewController(_:didFind:) to be called, or how would I get an instance of GKMatch? Here is the code I use to reproduce the issue, and below the reproduction steps. Code Run the attached project on an iPad and a Mac simultaneously. On both devices, tap the ship to connect to GameCenter. Create an automatched match by tapping the rightmost icon on both devices. When the two devices are matched, on iPad close the dialog and tap on the ship to disconnect from GameCenter. Wait some time until the Mac detects the disconnect and automatically sends an invitation to join again. When the notification arrives on the iPad, tap it, then tap the ship to connect to GameCenter again. The iPad receives the call player(_:didAccept:), but nothing else, so there’s no way to get a GKMatch instance again.
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Apr ’25
Game Center save game data to iCloud
We are trying to implement saving and fetching data to and from iCloud, but it have some problems. MacOS: 15.3 Here is what I do: Enable Game Center and iCloud capbility in Signing & Capabilities, pick iCloud Documents, create and select a Container. Sample code: void SaveDataToCloud( const void* buffer, unsigned int datasize, const char* name ) { if(!GKLocalPlayer.localPlayer.authenticated) return; NSData* data = [ NSData dataWithBytes:databuffer length:datasize]; NSString* filename = [ NSString stringWithUTF8String:name ]; [[GKLocalPlayer localPlayer] saveGameData:data withName:filename completionHandler:^(GKSavedGame * _Nullable savedGame, NSError * _Nullable){ if (error != nil) { NSLog( @"SaveDataToCloud error:%@", [ error localizedDescription ] ); } }]; } void FetchCloudSavedGameData() { if ( !GKLocalPlayer.localPlayer.authenticated ) return; [ [ GKLocalPlayer localPlayer ] fetchSavedGamesWithCompletionHandler:^(NSArray<GKSavedGame *> * _Nullable savedGames, NSError * _Nullable error) { if ( error == nil ) { for ( GKSavedGame *item in savedGames ) { [ item loadDataWithCompletionHandler:^(NSData * _Nullable data, NSError * _Nullable error) { if ( error == nil ) { //handle data } else { NSLog( @"FetchCloudSavedGameData failed to load iCloud file: %@, error:%@", item.name, [ error localizedDescription ] ); } } ]; } } else { NSLog( @"FetchCloudSavedGameData error:%@", [ error localizedDescription ] ); } } ]; } Both saveGameData and fetchSavedGamesWithCompletionHandler are not reporting any error, when debugging, saveGameData completionHandler got a nil error, and can get a valid "savedGame", but when try to rebot the game and use "fetchSavedGamesWithCompletionHandler" to fetch data, we got nothing, no error reported, and the savedGames got a 0 length. From this page https://developer.apple.com/forums/thread/718541?answerId=825596022#825596022 we try to wait 30sec after authenticated , then try fetchSavedGamesWithCompletionHandler, still got the same error. Checked: Game Center and iCloud are enabled and login with the same account. iCloud have enough space to save. So what's wrong with it.
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Mar ’25
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
Is there a way to get all the turnbasematches that can join
I am using Unity's GameKit to implement a turnbase game. I want to make a UI in Unity to show all the games I can join. I tried using var matches = await GKTurnBasedMatch.LoadMatches(); to get all the open matches. But it seems that I can only get the matcm related to the current apple account. Can you help me get all the matches? ALSO I used var match = await GKTurnBasedMatchmakerViewController.Request(request); to exit the gamecenter interface and start a game (automatic matching, no one was invited) Another device used var match = await GKTurnBasedMatch.Find(request); to find the game, but it did not find the game, but it start a new game (automatic matching). Can you help me solve these problems?
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176
Mar ’25
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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1.2k
Feb ’25
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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1.3k
Feb ’25
GameKit Matchmaking
Hi all im having a variety of issues with gamekit matchmaking. On the simulator the matchmaking ui pops up and I can click Quick Match, then immediately "Failed to find Players" this is the same with a real Apple ID and a sandbox account. If I use real devices the app at least discovers a match, but then the match none of the delegate methods for the match ever get called and the logs are filled with socket not connected and various errors. My questions are: Should match making via quick match work in the simulator, I have seen tutorial videos etc of this working, but I can't seem to get it to work. How do people debug issues with GameCenter / Gamekit to find out why its not able to connect? Many thanks in advance
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405
Feb ’25
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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2.1k
Feb ’25
GCDualSenseAdaptiveTrigger API set trigger mode not working
I'm trying to add support to PS5 DualSense controller. when I try to use the API from here: https://developer.apple.com/documentation/gamecontroller/gcdualsenseadaptivetrigger?language=objc None of the API works, am I missed anything? The code is like this: if ( [ controller.extendedGamepad isKindOfClass:[ GCDualSenseGamepad class ] ] ) { GCDualSenseGamepad * dualSenseGamePad = ( GCDualSenseGamepad * )controller.extendedGamepad; auto funcSetEffectTrigger = []( TriggerEffectParams& params, GCDualSenseAdaptiveTrigger *trigger ) { if ( params.m_mode == TriggerEffectMode::Off ) { [ trigger setModeOff ]; NSLog(@"setModeOff trigger.mode:%d", trigger.mode ); } else if ( params.m_mode == TriggerEffectMode::Feedback ) { [ trigger setModeFeedbackWithStartPosition: 0.2f resistiveStrength: 0.5f ]; } else if ( params.m_mode == TriggerEffectMode::Weapon ) { [ trigger setModeWeaponWithStartPosition: 0.2f endPosition: 0.4f resistiveStrength: 0.5f ]; } else if ( params.m_mode == TriggerEffectMode::Vibration ) { [ trigger setModeVibrationWithStartPosition: position amplitude: amplitude frequency: frequency ]; } }; if ( L2 ) { funcSetEffectTrigger( params, dualSenseGamePad.leftTrigger ); } if ( R2 ) { funcSetEffectTrigger( params, dualSenseGamePad.rightTrigger ); } } I've also tested to add "Game Controllers" capability to Target, still not working. Can't find anything else from the document or forums. I've no idea what need to do.
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639
Jan ’25
App keeps crashing due to Game Center account??
I play this game called Sonic Forces: Speed Battle that's available in the app store and I completed a quest outside of the app on this site called TapResearch for some rewards as I've done before and has worked, but after this one time I can no longer enter back into the game without crashing immediately. I tried deleting and reinstalling but nothing. I even tried signing into a different account but that didn't work either. So then I tried to make a new game center account to try and see if it works, and it did, though all my progress has been restarted. Does anyone know how to fix this?
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494
Jan ’25
Unity GameCenter Leaderboard issue
Hey, i have created a game in unity with the apple core and apple gamekit plugins present. I setup 5 leaderboards on the app store connect. I made a unity build and did the whole testflight build loop to test everything. When i open my gamecenter panel via the button i see my leaderboards but they show as MISSING TITLE which is weird because i have for sure set them up correctly they have a leaderboard reference name and leaderboard id as well. When debugging i can see that when i call my submit score function it gets submitted with no error but then i also dont see the score appear anywhere . Keep in mind the leaderboards are not live and are being tested on testflight first
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1.1k
Jan ’25
How set leaderboards to live
I’ve added two recurring leaderboards to my app and the user interface for the Game Center leaderboards pops up when expected and it lists the leaderboards but when you click on them it says “Have Fun With Friends” and lists some of my contacts instead of any scores. The status under Apple Connect is “Not Live” and I’m wondering how to activate them. App has been approved for external beta testing. On a related note, on my iPad it doesn’t display correctly, it says “Game Center” at the top but the rest of the UI doesn’t appear, just blackness.
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575
Jan ’25
Game Center achievements global players percent is 0%.
Hello, I’m the developer of the “stepsquad” app. Our app uses the Game Center achievement feature, but we’ve been encountering a problem: the “Global Players” always shows 0%, even though there are friends who have already achieved these achievements. Initially, I thought it might be because the app was newly launched. However, it’s now been over two months since release, and it’s still showing 0%. If anyone has any insight into this issue, please leave a comment.
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530
Jan ’25
Game Center Achievement "Global Players" Always Showing 0% Issue
Hello, I’m the developer of the “ StepSquad” app. Our app uses the Game Center achievement feature, but we’ve been encountering a problem: the “Global Players” metric always shows 0%, even though there are friends who have already achieved these achievements. Initially, I thought it might be because the app was newly launched. However, it’s now been over two months since release, and it’s still showing 0%. If anyone has any insight into this issue, please leave a comment.
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518
Jan ’25
Editor Ok, but running batch get: Cannot locate a Release or Debug Apple.GameKit native library for macOS
After running build.py -p Core GameKit and adding the tar balls to the Unity project in Assets/ExternalPackages no packages seem to be found when running the build using our continuous integration system. This was not the case when the project was opened in the Editor. It looks like in Apple.Core, the ApplePluginEnvironment hasn't run the OnEditorUpdate function and so the _appleUnityPackages Dictionary is empty. A change to ApplePlugInEnvironment.cs seemed to fix the issue: public static AppleNativeLibrary GetLibrary(string packageDisplayName, string appleBuildConfig, string applePlatform) { // ?FIX?: If we're not in the editor, we might not have updated the package list. if (_appleUnityPackages.Count == 0 && _updateState == UpdateState.Initializing) { OnEditorUpdate(); // UpdateState.Initializing OnEditorUpdate(); // UpdateState.Updating } I'm not sure if this is something we're doing incorrectly, the documentation for the plug-in mostly covered building the package.
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663
Dec ’24