导航栏按钮和项目未在 swift 3 中显示

我在 swift 中以编程方式使用导航栏，但无法在导航栏中显示栏按钮项目， 这是我所做的代码

override func viewDidLoad() {
        super.viewDidLoad()

  let navBar: UINavigationBar = UINavigationBar(frame: CGRect(x: 0, y: 0, width: 420, height: 65))
        self.view.addSubview(navBar)

        navBar.backgroundColor = hexStringToUIColor("4DC8BD")

        let navigationItem = UINavigationItem()

       self.title = "Transport APP"

        let btn1 = UIButton(type: .custom)
        btn1.setImage(UIImage(named: "Menu1"), for: .normal)
        btn1.frame = CGRect(x: 30, y: 30, width: 30, height: 30)
        btn1.addTarget(self, action: #selector(HomeViewController.menubuttonclick(_:)), for: .touchUpInside)
        let item1 = UIBarButtonItem(customView: btn1)


         self.navigationItem.setRightBarButtonItems([item1], animated: true)

}

    @IBAction func menubuttonclick(_ sender:UIBarButtonItem )
    {

        print("this menu button click")

    }

我可以尝试很多方法但没有得到结果 如何在导航栏中显示显示栏按钮项目，

你应该添加UINavigationItem给你的UINavigationBar and in item1需要添加在navitem看下面的代码

let navitem = UINavigationItem()
navitem.rightBarButtonItem = item1
navBar.setItems([navitem], animated: true)