GameCenter登录代码

参考:http://stackoverflow.com/questions/12870041/ios-6-game-center-authenticatehandler-cant-login-after-a-cancel

static BOOL g_isGameCenterInit = NO;
#define SYSTEM_VERSION_LESS_THAN(v) ([[[UIDevice currentDevice] systemVersion] 
compare:v options:NSNumericSearch] == NSOrderedAscending)
- (void)authenticateLocalUser:(id) sender
{
    if (g_isGameCenterInit) {
        [[NSNotificationCenter defaultCenter] postNotificationName:UIApplicationWillEnterForegroundNotification object:[UIApplication sharedApplication]];
        return;
    }
    g_isGameCenterInit = YES;
    
    GKLocalPlayer *localPlayer = [GKLocalPlayer localPlayer];
    // 已登录
    if (localPlayer.isAuthenticated) {
        [self sendOk];
    } else {
        
        if (SYSTEM_VERSION_LESS_THAN(@"6.0"))
        {
            // ios 5.x and below
            [localPlayer authenticateWithCompletionHandler:^(NSError *error)
             {
                 
                 if (localPlayer.isAuthenticated)
                 {
                     [self sendOk];
                 }
             }];
        }
        else
        {
            // ios 6.0 and above
            [localPlayer setAuthenticateHandler:(^(UIViewController* viewController, NSError *error) {
                [[CCDirector sharedDirector] resume];
                
                if (error && error.code == GKErrorCancelled) {
                    NSLog(@"Game Center code:%d %@", error.code, [error debugDescription]);
                    [self sendFaild];
                    return ;
                }
                if (localPlayer.isAuthenticated) {
                    [self sendOk];
                }
                else if (viewController) {
                    [[CCDirector sharedDirector] pause];
                    AppDelegate* delegate = (AppDelegate*)[UIApplication sharedApplication].delegate;
                    RootViewController* root = (RootViewController*)delegate.viewController;
                    [root presentViewController:viewController animated:YES completion:nil];
                }
            })];
        }
    }
}