Game Center doesn't save log in after quitting simulator and restarting simulator again

GKLocalPlayer *localPlayer = [GKLocalPlayer localPlayer];

localPlayer.authenticateHandler = ^(UIViewController *viewController, NSError *error){
if (viewController != nil){
[self presentViewController:viewController animated:YES completion:nil];

 GameCenterEnabled=YES;
 }
  else{}

 if ([GKLocalPlayer localPlayer].authenticated) {
  GameCenterEnabled=NO;    //GameCenterEnabled = BOOL
}
 else{
  GameCenterEnabled=YES;
 }
 };

For my universal device ios app, after I click the button for Game Center log in, it logs in and everything works fine. When I quit the simulator and turn on the simulator again, I have to re-log in to GameCenter again. Why doesn't the simulator save my log in? Is there a code to save Game Center as always logged in if you logged in once before?