Navigation Bar not showing title - ios

Question

I am unable to get the navigation bar to show the title that I specify. I have tried to change the title in the AppDelegate.m, as well as in the viewDidLoad of my first tab view. I suspect the title is being hidden, but I am unable fix it. Please provide any insight you may have.
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
navigationController = [[UINavigationController alloc] initWithNavigationBarClass:[CRGradientNavigationBar class] toolbarClass:nil];
UIColor *firstColor = [UIColor colorWithRed:155.0f/255.0f green:41.0f/255.0f blue:104.0f/255.0f alpha:1.0f];
UIColor *secondColor = [UIColor colorWithRed:215.0f/255.0f green:90.0f/255.0f blue:18.0f/255.0f alpha:1.0f];
NSArray *colors = [NSArray arrayWithObjects:firstColor, secondColor, nil];
[[CRGradientNavigationBar appearance] setBarTintGradientColors:colors];
self.navigationController.title = #"This title is not showing";
[[navigationController navigationBar] setTranslucent:NO];
//create the view controller for the first tab
self.firstViewController = [[FirstViewController alloc] initWithNibName:nil
bundle:NULL];
//create the view controller for the second tab
self.secondViewController = [[SecondViewController alloc] initWithNibName:nil
bundle:NULL];
//create the view controller for the third tab
self.thirdViewController = [[ThirdViewController alloc] initWithNibName:nil
bundle:NULL];
//create the view controller for the fourth tab
self.fourthViewController = [[FourthViewController alloc] initWithNibName:nil
bundle:NULL];
//create an array of all view controllers that will represent the tab at the bottom
NSArray *myViewControllers = [[NSArray alloc] initWithObjects:
self.firstViewController,
self.secondViewController, self.thirdViewController, self.fourthViewController, nil];
//initialize the tab bar controller
self.tabBarController = [[MainUITabBarController alloc] init];
//set the view controllers for the tab bar controller
[self.tabBarController setViewControllers:myViewControllers];
[navigationController setViewControllers:#[self.tabBarController]];
[self.window setRootViewController:navigationController];
self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}

Answer 1

The relationship of your view controllers isn't right.
The root view controller of your app should be the TabBarController.
Each of the items should have it's own Navigation Controller.
The title of each ViewController can be set in viewDidLoad() with self.title = "....

Answer 2

I've been able to set titles in the delegate as follows:
1.) Create view controllers
2.) Set those titles
3.) Then create UINavigationControllers and assign view controllers there
self.firstViewController = [[FirstViewController alloc] initWithNibName:nil bundle:nil];
self.secondViewController = [[SecondViewController alloc] initWithNibName:nil bundle:nil];
self.thirdViewController = [[ThirdViewController alloc] initWithNibName:nil bundle:nil];
self.fourthViewController = [[FourthViewController alloc] initWithNibName:nil bundle:nil];
[self.firstViewController setTitle:#"First"];
[self.secondViewController setTitle:#"Second"];
[self.thirdViewController setTitle:#"Third"];
[self.fourthViewController setTitle:#"Fourth"];
UINavigationController *controller1 = [[UINavigationController alloc] initWithRootViewController:self.firstViewController];
UINavigationController *controller2 = [[UINavigationController alloc] initWithRootViewController:self.secondViewController];
UINavigationController *controller3 = [[UINavigationController alloc] initWithRootViewController:self.thirdViewController];
UINavigationController *controller4 = [[UINavigationController alloc] initWithRootViewController:self.fourthViewController];
NSArray *viewControllers = [NSArray arrayWithObjects:controller1, controller2, controller3, controller4, nil];