iOS: Adding navigation bar from XIB

Question

I have been seeing this issue and resolving it by manually creating UINavigationController in the code. Could someone please tell me when I add Navigation Bar from XIB's Attribute Inspector -> Set Top bar to Black Navigation bar, it gets displayed in the XIB but when I run the program, it doesn't appear! I noticed that self.NavigationController was coming nil so I added UINavigationController in my XIB and assign NIB but still it's nil! What's wrong with this? Do I need any additional settings?

[EDIT1]

I tried adding it like below and it works but I want parent class to forward rotation and appearance events to child controller automatically. If I do following it won't send them because I am adding nvc as child and not marketsListViewController. So I thought I have to subclass UINavigationController. See EDIT2.

self.marketsListViewController = [[MarketsListViewController alloc] initWithNibName:@"MarketsListViewController" bundle:nil];
UINavigationController *nvc = [[UINavigationController alloc] initWithRootViewController:self.marketsListViewController];
nvc.navigationBar.barStyle = UIBarStyleBlack;
[self.marketsListView addSubview:nvc.view];

[self addChildViewController:nvc];
[nvc didMoveToParentViewController:self];

[EDIT2]

I have subclassed marketsListViewController to UINavigationController and thought following will work but it doesn't. It just displays navigation bar, UITableView doesn't get displayed!

self.marketsListViewController = [[MarketsListViewController alloc] initWithNibName:@"MarketsListViewController" bundle:nil];
self.marketsListViewController.navigationBar.barStyle = UIBarStyleBlack;
[self.marketsListView addSubview:self.marketsListViewController.view];

[self addChildViewController:self.marketsListViewController];
[self.marketsListViewController didMoveToParentViewController:self];

[EDIT3]

I was wrong in Edit1 that children controller won't get rotation events when I add child as navigation controller's root controller. Parent still sends all the events automatically and that's what I want! :)

Answer 1

Could someone please tell me when I add Navigation Bar from XIB's Attribute Inspector -> Set Top bar to Black Navigation bar, it gets displayed in the XIB but when I run the program, it doesn't appear!

What you see in you .xib file is just there to help you get your layout right and get a good idea of what it'll look like. When you have an app that uses a navigation bar, the bar is almost always managed by a navigation view controller (UINavigationController). The view controllers that the navigation controller hosts don't worry about the nav bar -- their view hierarchies go in the space beneath the bar.

So, the right way to get a navigation bar in your app is almost certainly to use a navigation controller. If you only have one view controller, make that that the navigation controller's root view controller (note: the root view controller of the window will be the navigation view controller). You can change the appearance of the bar from your view controller by setting the navigation bar's style:

self.navigationController.navigationBar.barStyle = UIBarStyleBlack;

Update: In the code you posted, you're just creating a new navigation controller, but not doing anything with it. I alluded above the the fact that (in most cases) the navigation controller should be the window's root view controller. It's fine to create your navigation controller in code, but you'll usually do it in the app delegate, and once you create it you'll set it as the window's root view controller. Here's an example borrowed from a project made fresh from Xcode's master/detail template (sans storyboards):

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    // Override point for customization after application launch.

    MasterViewController *masterViewController = [[MasterViewController alloc] initWithNibName:@"MMMasterViewController" bundle:nil];
    self.navigationController = [[UINavigationController alloc] initWithRootViewController:masterViewController];
    self.window.rootViewController = self.navigationController;
    [self.window makeKeyAndVisible];
    return YES;
}

Note that after creating the window and the navigation controller, the code sets the nav controller as the window's root view controller.