Right Button won't show in custom Navigation Controller - ios

Question

My app is a tab bar app with many navigation controllers.
I want these navigation controllers to handle login/logout actions with a custom right bar button. So I've set up my tab bar in AppDelegate this way :
MyFirstViewController *firstViewController = [[MyFirstViewController alloc] init];
UIViewController *firstNavigationController = [[CustomNavigationController alloc]
initWithRootViewController:firstViewController];
MySecondViewController *secondViewController = [[MySecondViewController alloc] init];
UIViewController *secondNavigationController = [[CustomNavigationController alloc]
secondViewController]
initWithRootViewController:secondViewController];
....
[tabBarController setViewControllers:#[firstNavigationController, secondNavigationController]];
Then CustomNavigationController :
#implementation ConnectionNavigationController
- (void) viewDidLoad
{
[self displayConnectionButton];
}
- (void) displayConnectionButton
{
UIImage *portraitImage, *landscapeImage;
portraitImage = [UIImage imageNamed:#"conn.png"];
landscapeImage = [UIImage imageNamed:#"connLandscape.png"];
UIBarButtonItem *connButton = [[UIBarButtonItem alloc]
initWithImage:[portraitImage
imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]
landscapeImagePhone:[landscapeImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]
style:UIBarButtonItemStylePlain target:self action:#selector(showConnectionPopup)];
self.navigationItem.rightBarButtonItem = connButton;
}
#end
I tried with viewDidLoad, viewDidAppear, viewWillAppear but nothing works, I can't get this button to show in the navigation bar. I also tried to add reloadInputViews or setNeedsDisplay. What should I do?
Thanks for your help
Edit : interface of CustomNavigationController
#interface ConnectionNavigationController : UINavigationController
- (void) displayConnectionButton;
#end

Answer 1

From what I understand you should add the displayConnectionButton method to the relevant UIViewController subclass and not to your UINavigationController subclass as this only contains the stack of view controllers.
E.g.
#implementation MyFirstViewController
- (void) viewDidLoad
{
[self displayConnectionButton];
}
- (void) displayConnectionButton
{
UIImage *portraitImage, *landscapeImage;
portraitImage = [UIImage imageNamed:#"conn.png"];
landscapeImage = [UIImage imageNamed:#"connLandscape.png"];
UIBarButtonItem *connButton = [[UIBarButtonItem alloc]
initWithImage:[portraitImage
imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]
landscapeImagePhone:[landscapeImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]
style:UIBarButtonItemStylePlain target:self action:#selector(showConnectionPopup)];
self.navigationItem.rightBarButtonItem = connButton;
}
#end
As a note if you put a breakpoint on your displayConnectionButton in your CustomNavigationController and po self.viewControllers I think you will get an empty array (i.e. no view controllers)