why my iOS11 navigationController doesn't to work

Question

I only want to show a large title.
My ViewController.swift look like:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        self.view.backgroundColor = UIColor.white

        title = "Hello world"
        self.navigationController?.navigationBar.prefersLargeTitles = true
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

}

But it doesn't work.

Answer 1

to show large title in navigationbar you need to make largeTitleDisplayMode .always add below lines of code into your viewDidLoad also don't forget to check ios11 or not

   title = "Hello world"

   if #available(iOS 11.0, *) {
        self.navigationController?.navigationBar.prefersLargeTitles = true
        self.navigationItem.largeTitleDisplayMode = .always
    }

and your UIViewController should have a UINavigationController If your UIViewController not embed in UINavigationController do the following steps

Open your storyboard -> select your view controller -> Editor -> Embed In -> NavigationController