从SKScene呼叫游戏中心排行榜

Question

您好我试图调用一个函数来显示SKScene的GameCenter LeaderBoard，但我没有成功。以下是我从SKScene调用该函数的方法。

class Menu: SKScene {
  func score(sender:UIButton!) {
  GamecenterUtils.sharedGamecenterUtils.showLeaderboardOnViewController(GamecenterUtils(),leaderboardID:"myleaderID")
 }
}

我收到编译错误＆＃39; GamecenterUtils＆＃39;不能转换为UIViewController。 但我这样做是因为GamecenterUtils是我的CGGameCenterControllDelegate。 这是GamecenterUtils类，而不是处理Game Center的所有内容：

private let _sharedGamecenterUtils = GamecenterUtils();

class GamecenterUtils : NSObject, GKGameCenterControllerDelegate {

    class var sharedGamecenterUtils : GamecenterUtils{
        return _sharedGamecenterUtils;
    }

    override init(){
    }

    func authenticateLocalUserOnViewController(viewController:UIViewController){
        var localPlayer:GKLocalPlayer = GKLocalPlayer.localPlayer();
        if (localPlayer.authenticated == false) {
            localPlayer.authenticateHandler = {(authViewController, error) -> Void in
                if (authViewController != nil) {
                    viewController.presentViewController(authViewController,animated:false,nil);
                }
            }
        }
        else {
            println("Already authenticated");
        }
    }
    func reportScore(score:Int,leaderboardID:NSString) {
        var scoreReporter:GKScore = GKScore(leaderboardIdentifier:"catchthategg01");
        scoreReporter.value = Int64(score);
        scoreReporter.context = 0;
        GKScore.reportScores([scoreReporter],{(error) -> Void in
            if let reportError = error {
                println("Unable to report score!\nError:\(error)");
            }
            else {
                println("Score reported successfully!");
            }
        });
    }

    func showLeaderboardOnViewController(viewController:UIViewController?, leaderboardID:NSString){
        if let containerController = viewController {
            var gamecenterController:GKGameCenterViewController = GKGameCenterViewController();
            gamecenterController.gameCenterDelegate = self;
            gamecenterController.viewState = GKGameCenterViewControllerState.Leaderboards;
            gamecenterController.leaderboardIdentifier = "catchthategg01";
            viewController?.presentViewController(gamecenterController,animated:false,nil);
        }
    }
    func gameCenterViewControllerDidFinish(_gameCenterViewController: GKGameCenterViewController!){
        _gameCenterViewController.dismissViewControllerAnimated(false,nil);
    }
}

感谢您的帮助。