Add a left bar button item to UINavigationController when no back button is present

Question

I'd like to add a default left bar button item to my navigation bar. It should only display when there is no back button supplied by the UINavigationController.

What is the best approach?

Answer 1

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {     if(navigationController.viewControllers.count != 1) { // not the root controller - show back button instead         return;     }     UIBarButtonItem *menuItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemOrganize                                                                               target:self                                                                               action:@selector(menuItemSelected:)];        [viewController.navigationItem setLeftBarButtonItem:menuItem];  } 

Answer 2

Swift code to add leftBarButtonItem…

    let leftMenuItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Done, target: self, action: "leftMenuItemSelected:");     self.navigationItem.setLeftBarButtonItem(leftMenuItem, animated: false); 

Update

For Swift 4 & above

    let leftMenuItem = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(leftMenuItemSelected(_:)))     self.navigationItem.setLeftBarButton(leftMenuItem, animated: false);