title: navigation bar right bar button items spacing
body: <p>I have created a <a href="https://i.stack.imgur.com/Fei7Z.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/Fei7Z.jpg" alt="navigation bar"></a>
   with left bar button item added from storyboard, titleView and three right bar button items from code.</p>
  
  <p>Here is the code:</p>
  
  <pre><code>override func viewDidLoad() {
      super.viewDidLoad()
  
      var screenWidth = UIScreen.mainScreen().bounds.width
      // custom title view
      var navBarWidth: CGFloat = self.navigationController!.navigationBar.frame.size.width
      let customTitleView = UIView(frame: CGRectMake(0, 0, navBarWidth, 44))
      titleLabel = UILabel(frame: CGRectMake(20, 0, navBarWidth, 40))
      titleLabel.text = conversationName
      if let titleFont = UIFont(name: "Roboto-Regular", size: 20) {
          titleLabel.font = titleFont
      }
      titleLabel.textColor = UIColor.whiteColor()
  
      customTitleView.addSubview(titleLabel)
      self.navigationItem.titleView = customTitleView
  
      // right bar buttons
      var searchImage = UIImage(named: "search")!
      var clipImage = UIImage(named: "clip")!
      var pencilImage = UIImage(named: "pencil")!
  
      var searchBtn = UIBarButtonItem(image: searchImage, style: UIBarButtonItemStyle.Plain, target: self, action: Selector("searchBtnPressed"))
      searchBtn.tintColor = UIColor.whiteColor()
      var clipBtn = UIBarButtonItem(image: clipImage, style: UIBarButtonItemStyle.Plain, target: self, action: Selector("clipBtnPressed"))
      clipBtn.tintColor = UIColor.whiteColor()
      var pencilBtn = UIBarButtonItem(image: pencilImage, style: UIBarButtonItemStyle.Plain, target: self, action: Selector("pencilBtnPressed"))
      pencilBtn.tintColor = UIColor.whiteColor()
  
      self.navigationItem.setRightBarButtonItems([pencilBtn, clipBtn, searchBtn], animated: false)
  }
  </code></pre>
  
  <p>My problem is that I want to change the spacing between right buttons but I don't know how. </p>
  
  <p>I've tried to add a fixedButton between them but it just increased the existing space. </p>
  
  <p>Can some one help me? Thanks.</p>