title: Can I find out the GameCenter user name that's actively logged in?
body: <p>I'd like my iphone app to pre-populate some fields once a user has logged into gamecenter. Specifically, the username!</p>
  
  <p>I have full logging in working - as well as a leaderboard and acheivements all working -  I just can't seem to find out how to access the users name property anywhere.</p>
  
  <p>Any advice / help would be greatly appreciated.</p>
  
  <p>Thanks,
  Kolya
  PS - This is my first question. Please be nice :-)</p>
  
  <p>Here is the code I'm trying:</p>
  
  <pre><code>if ([GameCenterManager isGameCenterAvailable]) {
  
      self.gameCenterManager = [[[GameCenterManager alloc] init] autorelease];
      [self.gameCenterManager setDelegate:self];
      [self.gameCenterManager authenticateLocalUser];
  
      NSLog(@"User alias: %@",[[GKLocalPlayer localPlayer]alias]);
  </code></pre>
  
  <p>But the NSLog outputs "User alias: (null)"?</p>