title: How to change RootViewController (in AppDelegate) from within CustomViewController?
body: <p>Good day,</p>
  
  <p>My app has authorization form (SigninController) which is loaded in AppDelegate, and after signing in (checking is in SigninController.m) TabBarController should appear (as main view of application).</p>
  
  <p>How can I change controller from Signin to TabBar and where ??</p>
  
  <pre><code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
    {  
  SigninController *aSigninController = [[SigninController alloc] initWithNibName:@"SigninView" bundle:nil];
  self.currentController = aSigninController;
  [aSigninController release];
  
  self.window.rootViewController = self.currentController;
  [self.window makeKeyAndVisible];
  return YES;
  }
  </code></pre>
  
  <p>SigninController.m</p>
  
  <pre><code>- (IBAction)signinClick
  {
  ........
  if (loginOK == YES)
  {        
        //This place is ready to send messages to show TabBar
  } else {
      UIAlertView *alert = ......
      [alert show];
      [alert release];
  }    
  }
  </code></pre>