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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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 ?
Hello!
Bare with me here, as there is a lot to explain!
I am working on implementing a Game Center high score leaderboard into my game. I have looked around for examples of how to properly implement this code, but have come up short on finding much material. Therefore, I have tried implementing it myself based off information I found on apples documentation.
Long story short, I am getting success printed when I update my score, but no scores are actually being posted (or at-least no scores are showing up on the Game Center leaderboard when opened).
Before I show the code, one thing I have questioned is the fact that this game is still in development. In AppStoreConnect, the status of the leaderboard is "Not Live". Does this affect scores being posted?
Onto the code. I have created a GameCenter class which handles getting the leaderboards and posting scores to a specific leaderboard. I will post the code in whole, and will discuss below what is happening.
PLEASE VIEW ATTACHED TEXT TO SEE THE GAMECENTER CLASS!
GameCenter class - https://developer.apple.com/forums/content/attachment/0dd6dca8-8131-44c8-b928-77b3578bd970
In a different GameScene, once the game is over, I request to post a new high score to Game Center with this line of code:
GameCenter.shared.submitScore(id: GameCenterLeaderboards.HighScore.rawValue)
Now onto the logic of my code. For the longest time I struggled to figure out how to submit a score. I figured out that in Xcode 12, they deprecated a lot of functions that previously worked for me. Not is seems that we have to load all leaderboards (or the ones we want). That is the purpose behind the leaderboards private variable in the Game Center class.
On the start up of the app, I call authenticate player. Once this callback is reached, I call loadLeaderboards which will load the leaderboards for each string id in an enum that I have elsewhere. Each of these leaderboards will be created as a Leaderboard object, and saved in the private leaderboard array. This is so I have access to these leaderboards later when I want to submit a score.
Once the game is over, I am calling submitScore with the leaderboard id I want to post to. Right now, I only have a high score, but in the future I may add a parameter to this with the value so it works for other leaderboards as well. Therefore, no value is passed in since I am pulling from local storage which holds the high score.
submitScore will get the leaderboard from the private leaderboard array that has the same id as the one passed in. Once I get the correct leaderboard, I submit a score to that leaderboard. Once the callback is hit, I receive the output "Successfully submitted score to leaderboard". This looks promising, except for the fact that no score is actually posted.
At startup, I am calling updatePlayerHighScore, which is not complete - but for the purpose of my point, retrieves the high score of the player from the leaderboard and is printing it out to the console. It is printing out (0), meaning that no score was posted.
The last thing I have questions about is the context when submitting a score. According to the documentation, this seems to just be metadata that GameCenter does not care about, but rather something the developer can use. Therefore, I think I can cross this off as causing the problem.
I believe I implemented this correctly, but for some reason, nothing is posting to the leaderboard. This was ALOT, but I wanted to make sure I got all my thoughts down.
Any help on why this is NOT posting would be awesome! Thanks so much!
Mark
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.
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.
GKAccessPoint triggerAccessPointWithState handler not invoked on iOS 26.0 and iOS 15.8.4
Incorrect/Unexpected Behaviour:
When calling [GKAccessPoint.shared triggerAccessPointWithState:GKGameCenterViewControllerStateAchievements handler:^{}] on a real device running iOS 26 beta (iOS 26), the overlay appears as expected, but the handler block is never called. This behavior also not working correctly on previous iOS versions(tested on iOS 15.8.4)
Steps to Reproduce:
Authenticate GKLocalPlayer
Call triggerAccessPointWithState:handler: with a block that logs or performs logic
Observe that overlay appears, but block is not executed
Behavior:
UI appears correctly
Handler is not invoked at all
Expected Result:
The handler should fire immediately after the dashboard is shown.
Actual Result:
The handler is never called.
Usecase:
As GKGameCenterViewController is deprecated we are moving to GKAccesspoint but due to above functionality issue we are unable to.
Environment:
Device: iPhone 16, iPhone 7
iOS: 26.0 and iOS 15.8.4
Xcode: 26.0 beta and Xcode 16.4
Has anyone come across the issue that setting GKLocalPlayer.local.authenticateHandler breaks a RealityView's world tracking on iOS / iPadOS 18 beta 5?
I'm in the process of upgrading my app to make use of the much appreciated RealityView unification, using RealityView not only on visionOS but now also on iOS and iPadOS. In my RealityView, I enable world tracking on iOS like this:
content.camera = .worldTracking
However, device position and orientation were ignored (the camera remained static) and there was no camera pass-through. Then I discovered that the issue disappeared when I remove the line
GKLocalPlayer.local.authenticateHandler = { viewController, error in
// ... some more code ...
}
So I filed FB14731139 and hope that it will be resolved before the release of iOS / iPadOS 18.
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()
}
}
}
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...
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
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?
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))")
}
}
}
I am developing a turn based game using GameKit. The happy path (pretty much as always) is fine; invite, accept, play, have winners/losers and match ends. Yay! But I am working on making sure I handle situations where invited friends decline to participate.
I've been through the docs, and don't see how the GKTurnBasedMatch is updated to reflect the tap of the decline button in the Game Center Invite notification. When I reload the match from Game Center on the host device the status for the invitee who declined is still .invited.
I also tested by setting all players that are not the host in the nextParticipants of the endTurn(...) to start the invites and the next invitee was not given a push notification to accept or decline the invite.
I feel like there should be a way to determine when an invitee has declined an invite (via participant in the match.participants via status OR a delegation method somewhere that is called when the Decline or Accept buttons on that notification are tapped.)
I'm missing something, please help me find it!
Thank you!
I have an idea for a game where the Apple TV app acts as the host and discovers nearby iOS apps that can join the game. Each iOS app needs to be able to have the user draw, tap, etc and have all the events be delivered in real time to the Apple TV where the effects will be rendered immediately (imagine a co-op game played in your lounge room where guests user their own devices to control aspects of the UI on the shared Apple TV screen)
MPC is discontinued and DeviceDiscoveryUI is limited to only a single iOS device so I’m trying to figure out the best way to do the P2P networking.
Reading/watching videos suggests that using GKMatchMaker and friends seems like it might suffer from latency problems (because everything has to go via Game Centre - or does it?) plus I’m not sure how I’d deal with the fact that the owner of the Apple TV is likely to signed into the same game centre id on both the Apple TV and their own devices to which would mean they wouldnt be able to play because the host can’t invite “themselves” on another device (or can it?)
Soooo… I’m looking for suggestions on how best to move forward. I’ve read https://developer.apple.com/documentation/technotes/tn3151-choosing-the-right-networking-api which is very useful but there’s no clear suggestion that would work.
Using the Network for the real time messaging seems doable but dealing with discovery / invites seems like a massive pain that I’d prefer to use built-in libraries if possible.
Any suggestions would be gladly received. Thanks a lot
Topic:
App & System Services
SubTopic:
Networking
Tags:
GameKit
Nearby Interaction
Multipeer Connectivity
Apple just introduced a new Challenges feature in Game Center (WWDC 2025). I have Game Center enabled for my app and have working leaderboards (and achievements). Now I want to implement challenges (connected to my leaderboards). But the Game Center Challenges not showing in App Store Connect or Xcode 16.4
I have a working GameCenterResources file in Xcode and it allows me to add Achievement, Leaderboard, Leaderboard Set, but no Challenges.
I'm based out of Europe. Any ideas?
Topic:
App Store Distribution & Marketing
SubTopic:
App Store Connect
Tags:
GameKit
App Store Connect
Xcode
Hello,
When testing GameKit "Manage Game Progress" in Xcode 26:
On iOS devices, achievements, leaderboards, and party code data display and work correctly.
On macOS devices, none of these data appear in "Manage Game Progress."
Is this a known issue with macOS GameKit, or is there a limitation compared to iOS?
If it is not a bug, is there any additional configuration needed to make achievements and leaderboards visible on macOS?
I also included the GameKit bundle in my macOS app and enabled Enable Debug Mode in GameKit Configuration in the scheme options.
Thank you.
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
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)
I facing to many lags in pubgmobile when i m playing its not running properly
Hello,
I setup a leaderboard in the default language English and everything works and the app is live in the store.
Now I am adding localization to the leaderboard and noticed than some languages have the data entry "Score Format Suffix" and some languages the data entries "Score Format Suffix (Singular)" and "Score Format Suffix (Plural)" instead.
Is this an error or intentional?
Kind Regards,
Chris
Topic:
App Store Distribution & Marketing
SubTopic:
App Store Connect
Tags:
App Store Connect
Localization
GameKit