UINavigationController + UITabBar. Wrong vertical positioning in viewDidLoad - iphone

Question

Using XCode 4.5 & iOS6
I created a UINavigationController with a UITabBar (NIBs) and the tab vertical positioning for the first launch is incorrect. When you click the second tab and again the first tab the vertical positioning is OK.
So ... How can I have the first tab properly positioned when the first run is done?
See wrong positioning:
http://img231.imageshack.us/img231/2159/badbf.png
My code:
AppDelegate.h
#interface bib_AppDelegate : UIResponder <UIApplicationDelegate, UITabBarControllerDelegate>
#property (strong, nonatomic) UIWindow *window;
#property (strong, nonatomic) UINavigationController *mainControllercode;
#property (strong, nonatomic) UITabBarController *tabBarController;
in the AppDelegate.m
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// change defaul selected icon tabbar color to orange
[[UITabBar appearance] setSelectedImageTintColor:[UIColor orangeColor]];
// Override point for customization after application launch.
UIViewController *viewController1 = [[agendaViewController alloc] initWithNibName:#"agendaViewController" bundle:nil];
UIViewController *viewController2 = [[messagesViewController alloc] initWithNibName:#"messagesViewController" bundle:nil];
self.tabBarController = [[UITabBarController alloc] init];
self.tabBarController.viewControllers = #[viewController1, viewController2];
self.mainControllercode = [[UINavigationController alloc] initWithRootViewController:self.tabBarController];
self.window.rootViewController = self.mainControllercode;
[self.window makeKeyAndVisible];
return YES;
}
agendaViewController.h
#import <UIKit/UIKit.h>
#interface agendaViewController : UIViewController
#end
agendaViewController.m
#import "agendaViewController.h"
#interface agendaViewController ()
#end
#implementation agendaViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
self.title = NSLocalizedString(#"Agenda", #"Agenda");
self.tabBarItem.image = [UIImage imageNamed:#"83-calendar"];
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
EDIT 1:
I created a sample project with Storyboards that you can see. I would like to have the same features without Storyboards, download this here:
http://www.freefilehosting.net/atestsb
Thanks

Answer 1

You are going about this the wrong way.
A UITabBarController should have a collection of UINavigationControllers which then have their root controller set to the primary Nib. Each tab then handles its own navigation stack.
You are currently putting the UITabBarController inside the root of the UINavigationController. This will cause issues as well as remove the tab bar when you move through the navigation stack.
Check out this link for more details to handle it programmatically :
http://www.xdracco.net/howto-implement-uinavigationcontroller-uitabbarcontroller-programmatically/