EDIT: Solution : add the buttons to UIViewControllers and no to UINavigationControllers
My application's root view controller is a uitabbarcontroller who contains an array of 5 navigation controllers, all initialized in app delegate. All works good but I have just one problem : I can't add any button in the navigation bar of the controllers contained in the tabbarcontroller from the app delegate. I can set their navigation bar's title, their navigation bar's background etc but when I add a button in their navigation bar, I have no error but the button isn't displayed.
Is anyone know the reason of that ? Is it forbidden to do that ?
Precision 1: I use .xib files for views, I don't use any storyboard.
Precision 2: this is the code I'm using to create the button for each controller :
UIBarButtonItem *myBarBtn = [[UIBarButtonItem alloc]initWithImage:[UIImage imageNamed:@"icon-chrono"] style:UIBarButtonItemStylePlain target:nil action:nil];
[ret.navigationItem setRightBarButtonItem:myBarBtn animated:YES];
Precision 3: when I copy this code in each navigation controller viewDidLoad method, it works
EDIT: it's not a problem with the image, the problem is the same when I use initWithTitle method to create the UIBarButtonItem
