title: how to set title to first navigation controller in a page that uses tab view controller.?
body: <p>we have used the following code in app delegate. but we are getting error in the setTitle function of navigation controller.</p>
  
  <pre><code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
  {
      self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
      // Override point for customization after application launch.
      UIViewController *viewController1 = [[FirstViewController alloc] initWithNibName:@"FirstViewController" bundle:nil];
      UIViewController *viewController2 = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
      UIViewController* viewController3=[[ThirdViewController alloc]initWithNibName:@"ThirdViewController" bundle:nil];
      self.tabBarController = [[UITabBarController alloc] init];
      self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2,viewController3, nil];
      NavigationViewController* navigationViewController=[[NavigationViewController alloc]initWithRootViewController:self.tabBarController];
    self.navigationItem.title=@"news";
      self.window.rootViewController = navigationViewController;
      [self.window makeKeyAndVisible];
  
      return YES;
  }
  </code></pre>