如何在没有UINavigationController的情况下向导航栏添加多个按钮？

Question

在UINavigationController中为viewController添加一个多按钮， 我只是这一行：

self.navigationItem.rightBarButtonItems = [my button]

但我没有成功将其添加到UINavigationController的视图中：

 //create new navigation item. and add it to the nvigation bar
        customNavigationItem = UINavigationItem()

        /* now we need to add the menu + search to the navigation item */
        //create search button
        let searchButton = UIButton();
        searchButton.frame = CGRectMake(0, 0, 50.0, 50.0);
        searchButton.backgroundColor = UIColor.redColor();
        searchButton.titleLabel!.font = UIFont.iconmoonFont(14.0)
        searchButton.titleLabel?.textColor = UIColor.whiteColor()
        searchButton.titleLabel!.text = IconsConstants.SEARCH;//SEARCH ICON TEXT
        searchButton.backgroundColor = UIColor.clearColor();
        searchButton.contentHorizontalAlignment = UIControlContentHorizontalAlignment.Center;
        searchButton.contentVerticalAlignment = UIControlContentVerticalAlignment.Center;
        let searchUIbarBtn = UIBarButtonItem.init(customView: searchButton)

        //create menu button
        let menuButton = UIButton();
        menuButton.frame = CGRectMake(0, 0, 40.0, 40.0);
        menuButton.titleLabel!.font = UIFont.iconmoonFont(14.0)
        menuButton.backgroundColor = UIColor.whiteColor()
        menuButton.titleLabel!.text = IconsConstants.MENU;//SEARCH ICON TEXT
        menuButton.backgroundColor = UIColor.clearColor();
        menuButton.contentHorizontalAlignment = UIControlContentHorizontalAlignment.Center;
        menuButton.contentVerticalAlignment = UIControlContentVerticalAlignment.Center;
        let menuUIbarBtn = UIBarButtonItem.init(customView: menuButton)

        //add button to NavigationItem
        customNavigationItem.rightBarButtonItems = [menuUIbarBtn,searchUIbarBtn];


        /* add navigation bar */
        navigationBar = UINavigationBar();
        navigationBar.frame = CGRectMake(0, statusBarHeight, self.view.frame.size.width, 44);
        //navigationBar.translucent = false
        navigationBar.barTintColor = UIColor.statusBarColor()
        navigationBar.items = [customNavigationItem]


        self.view.addSubview(navigationBar)

我无法理解为什么我的酒吧没有任何按钮？