Assuming that you've enabled Game Center in your app and also added a leaderboard in iTunes Connect then you need to authenticate your player before you can show GC. Also, be sure that you've created a test user in iTunes Connect that you can use to log in to Game Center when the prompt appears.
Your MenuViewController should authenticate the local player in viewDidLoad like so:
class MenuViewController: UIViewController,
GKGameCenterControllerDelegate
{
var leaderboardIdentifier: String? = nil
var gameCenterEnabled: Bool = false
override func viewDidLoad()
{
super.viewDidLoad()
//Your code that sets up your scene or other set up code
//HERE IS WHERE YOU AUTHENTICATE
authenticateLocalPlayer()
}
func authenticateLocalPlayer()
{
var localPlayer = getLocalPlayer() // see GKLocalPlayerHack.h
localPlayer.authenticateHandler =
{ (viewController : UIViewController!, error : NSError!) -> Void in
if viewController != nil
{
self.presentViewController(viewController, animated:true, completion: nil)
}
else
{
if localPlayer.authenticated
{
self.gameCenterEnabled = true
localPlayer.loadDefaultLeaderboardIdentifierWithCompletionHandler
{ (leaderboardIdentifier, error) -> Void in
if error != nil
{
print("error")
}
else
{
self.leaderboardIdentifier = leaderboardIdentifier
print("\(self.leaderboardIdentifier)") //in your example "VHS" should be returned
}
}
}
else
{
print("not able to authenticate fail")
self.gameCenterEnabled = false
if error
{
print("\(error.description)")
}
else
{
print( "error is nil")
}
}
}
}
}
func gameCenterViewControllerDidFinish(gameCenterViewController: GKGameCenterViewController!)
{
gameCenterViewController.dismissViewControllerAnimated(true, completion: nil)
}
}
After you've successfully authenticated then you should be able to present Game Center.
Note the line:
var localPlayer = getLocalPlayer() // see GKLocalPlayerHack.h
To get that to work you need to do a little hack to get GKLocalPlayer to instantiate correctly in Swift.
Create a new class in Objective-C and name the file GKLocalPlayerHack.h/m
In the header put:
// GKLocalPlayerHack.h
// Issue with GameKit and Swift
// https://stackoverflow.com/questions/24045244/game-center-not-authenticating-using-swift
#import <GameKit/GameKit.h>
@interface GKLocalPlayerHack : NSObject
GKLocalPlayer *getLocalPlayer(void);
@end
In the implementation file put:
// GKLocalPlayerHack.m
// Issue with GameKit and Swift
// https://stackoverflow.com/questions/24045244/game-center-not-authenticating-using-swift
#import "GKLocalPlayerHack.h"
@implementation GKLocalPlayerHack
GKLocalPlayer *getLocalPlayer(void)
{
return [GKLocalPlayer localPlayer];
}
@end
Be sure to add:
#import "GKLocalPlayerHack.h"
To your bridging header.
Credit to @marmph for his answer in this question: Game Center not authenticating using Swift
