Configuring the backBarButtonItem of a View Controller's Navigation Item in a Storyboard

Question

It's easy enough to drag and drop bar button items onto a view controller's navigation bar in a storyboard in Interface Builder. In this way, you can set the leftBarButtonItem and rightBarButtonItem outlets of the view controller's navigation item. But there's also a backBarButtonItem outlet, and it's not obvious at all how to set it. How can I set a custom back bar button item using Interface Builder?

Answer 1

• Select the view controller whose navigation items you want to change. The black bar displaying the identity of the view controller changes to an iconified tray of its referenced objects.

• Drag and drop a bar button item from the object library onto the tray.

• Right-click on the view controller's navigation item in the main object tray on the left-hand side. Wire up the newly added button as the navigation item's backBarButtonItem outlet.

• Select the bar button and configure it in any way you choose with the Attributes Inspector.

Answer 2

As @wcochran noted above, when working with viewControllers pushed onto a navigationController's stack, the backBarButtonItem outlet is already wired and can't be changed. Furthermore, selecting the child VC's navigationItem and changing the Back Button text in IB doesn't do what you would expect.

Now you might think that replacing the child VC's backBarButtonItem would solve the problem, but it doesn't. Confusingly, if you want to set the title of the back button of a child VC, you have to set the back button title of its parent (!), like so:

- (void)viewWillAppear:(BOOL)animated // in the parent VC!
{
    UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:nil action:nil];
    self.navigationItem.backBarButtonItem = backButton;
}

This won't do anything on the parent VC. In fact, if the parent is the navigationController's RootViewController, there won't be a back button at all. But the child will inherit (or pick up) the back button you've created.

This only applies to the immediate child VC, so if you want to maintain the label down through the navigationController's stack you need to set it on each parent.

Thanks to @wiliz in #iphonedev for explaining this to me.