Ios 导航栏可以'；不显示标题

我创建了一个UINavigationController对象，但它无法设置标题

class LogInSwitchingViewController: UINavigationController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        self.view.backgroundColor = UIColor.white

        self.navigationItem.title = "This is title"
        self.navigationBar.tintColor = UIColor.black

        let vc1 = UIViewController()
        vc1.view.backgroundColor = UIColor.brown
        self.pushViewController(vc1, animated: true)
    }

---

您需要更新可见视图控制器的

标题

属性，而不是导航控制器本身：

let vc1 = UIViewController()
vc1.title = "This is title"
vc1.view.backgroundColor = UIColor.brown
self.pushViewController(vc1, animated: true)