title: Adding a UIBarButtonItem programmatically to UINavigationBar
body: <p>I dropped in a <code>UINavigationBar</code> in <code>UIInterfaceBuilder</code>. I present this view modally and just want a <code>UIBackBarButton</code> to return to my last view.  I have an outlet and property to this <code>UINavigationBar</code> declared.  I thought in my <code>viewDidLoad</code> method, I could create a <code>UIBackButton</code> like this:</p>
  
  <pre><code>UIBarButtonItem *backButton = 
  [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonItemStyleBordered 
                                                target:self 
                                                action:@selector(goBack)];
  self.navigationItem.backBarButtonItem = backButton;
  [backButton release];
  </code></pre>
  
  <p>But I do not see my <code>UIBackBarButtonItem</code> on the <code>UINavigationBar</code>.  I think I am doing something wrong here since I don't think my <code>UINavigationBar</code> knows I'm trying to add this <code>UIBackBarButtonItem</code> to it in this way.  Would I have to do create an <code>NSArray</code>, put the button in it, and setItems for the NavigationBar instead?  </p>
  
  <p>I'm confused on how the navigationItem property works vs the setItems of the <code>UINavigationBar</code> as well.  Any help would be appreciated.  Thanks!</p>