Question

In AppDelegate.m I am writing following code for navigationbar.

MaterialsListViewController *materials = [[MaterialsListViewController alloc]initWithNibName:@"MaterialsListView" bundle:nil];
    UINavigationController *navigation = [[UINavigationController alloc]initWithRootViewController:materials];

In the same AppDelegate.m I am writing following code for tabbar.

UIViewController *viewController1, *viewController2;
viewController1 = [[[MaterialsListViewController alloc] initWithNibName:@"MaterialsList" bundle:nil] autorelease];
viewController2 = [[[RecentMaterialsListViewController alloc] initWithNibName:@"RecentMaterialsList" bundle:nil] autorelease];
self.tabBarController = [[[UITabBarController alloc] init] autorelease];
self.tabBarController.viewControllers = [NSArray arrayWithObjects:viewController1, viewController2, nil];
NSArray *items = self.tabBarController.tabBar.items;
UITabBarItem *item1 = [items objectAtIndex:0];
[item1 setTitle:@"Materials"];
UITabBarItem *item2 = [items objectAtIndex:1];
[item2 setTitle:@"Recent"];
self.window.rootViewController = self.tabBarController;

How to add NavigationBar to the tabbar?

Answer 1

You are missing the UINavigationController.

After you cretae viewController1

init a UINavigationController with a your viewController has RootViewController:

UINavigationController *navigationController_01 = [[UINavigationController alloc] initWithRootViewController:(UIViewController *)];

Then add the navigationController_01 to tabBarController.viewControllers:

self.tabBarController.viewControllers = [NSArray arrayWithObjects:navigationController_01, navigationController_02, nil];