iPad的游戏中心

GKLeaderboardViewController *leaderboardController = [[[GKLeaderboardViewController alloc] init] autorelease];
if (leaderboardController != nil) {
  // start the leader board view controller
  leaderboardController.leaderboardDelegate = self;
  leaderboardController.timeScope = GKLeaderboardTimeScopeAllTime;
  leaderboardController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
  leaderboardController.modalPresentationStyle = UIModalPresentationFullScreen;
  leaderboardController.category = @\"map1\";
  RootViewController* rootVC = ((AppDelegate*)[UIApplication   sharedApplication].delegate).viewController;
  [rootVC presentModalViewController:leaderboardController animated:YES];
}

leaderboardController.modalPresentationStyle = UIModalPresentationFullScreen;