title: UIBarButtonItem, add a back button using Swift
body: <p>I want to add a back button to my webview app. </p>
  
  <p>Looking through <code>UIBarButtonItem</code>, I can't seem to find a back button. See code:</p>
  
  <pre><code>override func viewDidLoad() {
      super.viewDidLoad()
      // Do any additional setup after loading the view, typically from a nib.
  
      let url = NSURL(string: "http://google.com")!
      webView.loadRequest(NSURLRequest(URL: url))
      webView.allowsBackForwardNavigationGestures = true
  
      let refresh = UIBarButtonItem(barButtonSystemItem: .Refresh, target: webView, action: #selector(webView.reload))
  
      let back = UIBarButtonItem(barButtonSystemItem: .Back, target: webView, action: #selector(webView.goBack))
  
      toolbarItems = [back, refresh]
      navigationController?.toolbarHidden = false
  
  }
  </code></pre>
  
  <p>How do I add a back button to the toolbar?</p>