Cant receive game center invitations

Question

I am trying to develop a realtime multiplayer game for IOS by using cocos2d by using the tutorial on http://www.raywenderlich.com/3325/how-to-make-a-simple-multiplayer-game-with-game-center-tutorial-part-22

Everything works fine including auto matching with a random player but inviting a friend doesn't work because other device cannot receive an invitation.

When I clicked on invite friends button and then selected a friend by using the standard game center interface, it says waiting (forever) and nothing happens. My friend cannot receive an invitation from game center (no notifications).

I can invite a friend by using nearby friends functionality (when this functionality is enabled on both devices) but no invitation notification when nearby friends is disabled.

I spent hours and hours for searching on Google, found similar cases but no solution.

Some early feedback about possible answers:

• I use two devices (one iPhone and one iPad), no simulator
• All settings on iTunes connect are fine including multiplayer settings
• I validated that both devices are connected to sandbox by using different test accounts
• I've already checked the notification settings for Game center on both devices
• I've already checked all proxy/firewall issues and tried on both WiFi and Cellular for both devices
• Game invitations are enabled for both of the devices/accounts
• I've already checked the bundle IDs, app version IDs, etc...
• Both of the devices are IOS 6.x and App target version os IOS 5.0
• I have no other issues about game center (leaderboards, random matchmaking, etc... all fine)
• I call the inviteHandler method as soon after I authenticated a user as possible as mentioned in Apple documentation.

Here is my Game center helper class Header file:

#import <Foundation/Foundation.h>
#import <GameKit/GameKit.h>
@protocol GCHelperDelegate
- (void)matchStarted;
- (void)matchEnded;
- (void)match:(GKMatch *)match didReceiveData:(NSData *)data
fromPlayer:(NSString *)playerID;
- (void)inviteReceived;
@end

@interface GCHelper : NSObject <GKMatchmakerViewControllerDelegate, GKMatchDelegate>{
BOOL gameCenterAvailable;
BOOL userAuthenticated;

UIViewController *presentingViewController;
GKMatch *match;
BOOL matchStarted;
id <GCHelperDelegate> delegate;

NSMutableDictionary *playersDict;

GKInvite *pendingInvite;
NSArray *pendingPlayersToInvite;
NSMutableArray *unsentScores;
}

@property (retain) GKInvite *pendingInvite;
@property (retain) NSArray *pendingPlayersToInvite;

@property (assign, readonly) BOOL gameCenterAvailable;

@property (retain) NSMutableDictionary *playersDict;

@property (retain) UIViewController *presentingViewController;
@property (retain) GKMatch *match;
@property (assign) id <GCHelperDelegate> delegate;

- (void)findMatchWithMinPlayers:(int)minPlayers maxPlayers:(int)maxPlayers
             viewController:(UIViewController *)viewController
                   delegate:(id<GCHelperDelegate>)theDelegate;

- (BOOL) reportAchievementIdentifier: (NSString*) identifier percentComplete: (float) percent;

+ (GCHelper *)sharedInstance;
- (void)authenticateLocalUser;

@end

And here is the implementation of the game center helper class

#import "GCHelper.h"

@implementation GCHelper

@synthesize gameCenterAvailable;

@synthesize presentingViewController;
@synthesize match;
@synthesize delegate;
@synthesize playersDict;
@synthesize pendingInvite;
@synthesize pendingPlayersToInvite;

#pragma mark Initialization

static GCHelper *sharedHelper = nil;
+ (GCHelper *) sharedInstance {
    if (!sharedHelper) {
        sharedHelper = [[GCHelper alloc] init];
    }
    return sharedHelper;
}
- (BOOL)isGameCenterAvailable {
    // check for presence of GKLocalPlayer API
    Class gcClass = (NSClassFromString(@"GKLocalPlayer"));

    // check if the device is running iOS 4.1 or later
    NSString *reqSysVer = @"4.1";
    NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
    BOOL osVersionSupported = ([currSysVer compare:reqSysVer
                                           options:NSNumericSearch] != NSOrderedAscending);

    return (gcClass && osVersionSupported);
}
- (id)init {
    if ((self = [super init])) {
        gameCenterAvailable = [self isGameCenterAvailable];
        if (gameCenterAvailable) {
            NSNotificationCenter *nc =
            [NSNotificationCenter defaultCenter];
            [nc addObserver:self
                   selector:@selector(authenticationChanged)
                       name:GKPlayerAuthenticationDidChangeNotificationName
                     object:nil];
        }
    }
    return self;
}
- (void)authenticationChanged {

    if ([GKLocalPlayer localPlayer].isAuthenticated && !userAuthenticated) {
        NSLog(@"Authentication changed: player authenticated.");
        userAuthenticated = TRUE;

        [GKMatchmaker sharedMatchmaker].inviteHandler = ^(GKInvite *acceptedInvite, NSArray *playersToInvite) {

            NSLog(@"Received invite");
            self.pendingInvite = acceptedInvite;
            self.pendingPlayersToInvite = playersToInvite;
            [delegate inviteReceived];

        };

    } else if (![GKLocalPlayer localPlayer].isAuthenticated && userAuthenticated) {
        NSLog(@"Authentication changed: player not authenticated");
        userAuthenticated = FALSE;
    }

}
- (void)lookupPlayers {

    NSLog(@"Looking up %d players...", match.playerIDs.count);
    [GKPlayer loadPlayersForIdentifiers:match.playerIDs withCompletionHandler:^(NSArray *players, NSError *error) {

        if (error != nil) {
            NSLog(@"Error retrieving player info: %@", error.localizedDescription);
            matchStarted = NO;
            [delegate matchEnded];
        } else {

            // Populate players dict
            self.playersDict = [NSMutableDictionary dictionaryWithCapacity:players.count];
            for (GKPlayer *player in players) {
                NSLog(@"Found player: %@", player.alias);
                [playersDict setObject:player forKey:player.playerID];
            }

            // Notify delegate match can begin
            matchStarted = YES;
            [delegate matchStarted];

        }
    }];

}

#pragma mark User functions

- (void)authenticateLocalUser {

    if (!gameCenterAvailable) return;

    NSLog(@"Authenticating local user...");
    if ([GKLocalPlayer localPlayer].authenticated == NO) {
        [[GKLocalPlayer localPlayer] authenticateWithCompletionHandler:nil];
    } else {
        NSLog(@"Already authenticated!");
    }
}

- (void)findMatchWithMinPlayers:(int)minPlayers maxPlayers:(int)maxPlayers viewController:(UIViewController *)viewController delegate:(id<GCHelperDelegate>)theDelegate {

    if (!gameCenterAvailable) return;

    matchStarted = NO;
    self.match = nil;
    self.presentingViewController = viewController;
    delegate = theDelegate;

    if (pendingInvite != nil) {

        [presentingViewController dismissModalViewControllerAnimated:NO];
        GKMatchmakerViewController *mmvc = [[[GKMatchmakerViewController alloc] initWithInvite:pendingInvite] autorelease];
        mmvc.matchmakerDelegate = self;
        [presentingViewController presentModalViewController:mmvc animated:YES];

        self.pendingInvite = nil;
        self.pendingPlayersToInvite = nil;

    } else {

        [presentingViewController dismissModalViewControllerAnimated:NO];
        GKMatchRequest *request = [[[GKMatchRequest alloc] init] autorelease];
        request.minPlayers = minPlayers;
        request.maxPlayers = maxPlayers;
        request.playersToInvite = pendingPlayersToInvite;

        GKMatchmakerViewController *mmvc = [[[GKMatchmakerViewController alloc] initWithMatchRequest:request] autorelease];
        mmvc.matchmakerDelegate = self;

        [presentingViewController presentModalViewController:mmvc animated:YES];

        self.pendingInvite = nil;
        self.pendingPlayersToInvite = nil;

    }

}

#pragma mark GKMatchmakerViewControllerDelegate

// The user has cancelled matchmaking
- (void)matchmakerViewControllerWasCancelled:(GKMatchmakerViewController *)viewController {
    [presentingViewController dismissModalViewControllerAnimated:YES];
}

// Matchmaking has failed with an error
- (void)matchmakerViewController:(GKMatchmakerViewController *)viewController didFailWithError:(NSError *)error {
    [presentingViewController dismissModalViewControllerAnimated:YES];
    NSLog(@"Error finding match: %@", error.localizedDescription);
}

// A peer-to-peer match has been found, the game should start
- (void)matchmakerViewController:(GKMatchmakerViewController *)viewController didFindMatch:(GKMatch *)theMatch {
    [presentingViewController dismissModalViewControllerAnimated:YES];
    self.match = theMatch;
    match.delegate = self;
    if (!matchStarted && match.expectedPlayerCount == 0) {
        NSLog(@"Ready to start match!");
        [self lookupPlayers];
    }
}

#pragma mark GKMatchDelegate

// The match received data sent from the player.
- (void)match:(GKMatch *)theMatch didReceiveData:(NSData *)data fromPlayer:(NSString *)playerID {
    if (match != theMatch) return;

    [delegate match:theMatch didReceiveData:data fromPlayer:playerID];
}

// The player state changed (eg. connected or disconnected)
- (void)match:(GKMatch *)theMatch player:(NSString *)playerID didChangeState:(GKPlayerConnectionState)state {
    if (match != theMatch) return;

    switch (state) {
        case GKPlayerStateConnected:
            // handle a new player connection.
            NSLog(@"Player connected!");

            if (!matchStarted && theMatch.expectedPlayerCount == 0) {
                NSLog(@"Ready to start match!");
                [self lookupPlayers];
            }

            break;
        case GKPlayerStateDisconnected:
            // a player just disconnected.
            NSLog(@"Player disconnected!");
            matchStarted = NO;
            [delegate matchEnded];
            break;
    }
}

// The match was unable to connect with the player due to an error.
- (void)match:(GKMatch *)theMatch connectionWithPlayerFailed:(NSString *)playerID withError:(NSError *)error {

    if (match != theMatch) return;

    NSLog(@"Failed to connect to player with error: %@", error.localizedDescription);
    matchStarted = NO;
    [delegate matchEnded];
}

// The match was unable to be established with any players due to an error.
- (void)match:(GKMatch *)theMatch didFailWithError:(NSError *)error {

    if (match != theMatch) return;

    NSLog(@"Match failed with error: %@", error.localizedDescription);
    matchStarted = NO;
    [delegate matchEnded];
}

- (void)reportScore:(int64_t)score forCategory:(NSString *)category {
    // Only execute if OS supports Game Center & player is logged in
    if ([self isGameCenterAvailable] && [GKLocalPlayer localPlayer].authenticated == YES)
    {
        // Create score object
        GKScore *scoreReporter = [[[GKScore alloc] initWithCategory:category] autorelease];

        // Set the score value
        scoreReporter.value = score;

        // Try to send
        [scoreReporter reportScoreWithCompletionHandler:^(NSError *error) {
            if (error != nil)
            {
                // Handle reporting error here by adding object to a serializable array, to be sent again later
                [unsentScores addObject:scoreReporter];
            }
        }];
    }
}

- (BOOL) reportAchievementIdentifier: (NSString*) identifier percentComplete: (float) percent {

    if ([self isGameCenterAvailable] && [GKLocalPlayer localPlayer].authenticated == YES)
    {
        GKAchievement *achievement = [[[GKAchievement alloc] initWithIdentifier: identifier] autorelease];
        if (achievement)
        {
            achievement.percentComplete = percent;
            [achievement reportAchievementWithCompletionHandler:^(NSError *error)
             {
                 if (error != nil)
                 {
                     // Retain the achievement object and try again later (not shown).
                 }
             }];
        }

        return YES;
    }

    return NO;
}


@end

And Finally this is how I call the game center from my game layer (I tried two different options but none of them worked)

Option 1

[[GCHelper sharedInstance] findMatchWithMinPlayers:2 maxPlayers:2 viewController: [[[UIApplication sharedApplication] keyWindow] rootViewController] delegate: self];

Option 2

AppController *app = (AppController*) [[UIApplication sharedApplication] delegate];
        UINavigationController *viewController = [app navController];
        [[GCHelper sharedInstance] findMatchWithMinPlayers:2 maxPlayers:2 viewController:viewController delegate:self];

Any help will be appreciated. Thanks in advance...

Answer 1

Ok, it seems that it again works without any changes in our code or network settings. I opened ticket to Apple support, bug records, etc... and it seems that some of them worked...

Now we understand that it was a bug in Game Center sandbox. As far as I see, sanbox version of game center is not that stable and people in Apple don't give enough attention to this service. There is also no way to check the system status on the internet.

I'm still continuing to discuss with Apple support in order to understand the reason and will share the all conversation here when it's completed.

Happy coding...

Answer 2

I've been dealing with multiplayer for a few months now and invitations have been a real issue for me....and like you, I used Ray's tutorial to get me started. I realized today that Ray's code has a bug in it where invites will not work if both clients have the GKMatchmakerView up. You need to dismiss it when you first receive the invite with something along the lines of:

        [gcdelegate.viewController  dismissViewControllerAnimated:YES
                                 completion:^{
                                     GKMatchmakerViewController *mmvc = [[GKMatchmakerViewController alloc] initWithInvite:pendingInvite];
                                     mmvc.matchmakerDelegate = self;
                                     [gcdelegate.viewController presentModalViewController:mmvc animated:YES];
                                     self.pendingInvite = nil;
                                     self.pendingPlayersToInvite = nil;
                                     boo_invite=true;
                                 }];