UINavigationBarにUISearchBarを追加する

class ViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let searchController = UISearchController(searchResultsController: SearchResultViewController())
        searchController.searchResultsUpdater = self
        //これがないとios13以下の端末で真っ白に表示される
        searchController.modalPresentationStyle = .popover
        navigationItem.searchController = searchController
    }
    
}
extension ViewController: UISearchResultsUpdating {
    func updateSearchResults(for searchController: UISearchController) {
        let text = searchController.searchBar.text ?? ""
        print(text)
    }
}

class SearchResultViewController: UIViewController {
    
    let arr = ["hoge", "huga", "piyo"]
    
    @IBOutlet weak var tableView: UITableView! {
        didSet {
            tableView.delegate = self
            tableView.dataSource = self
            tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell")
        }
    }
    override func viewDidLoad() {
        super.viewDidLoad()
        
    }
}

extension SearchResultViewController: UITableViewDelegate, UITableViewDataSource {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return arr.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
        cell.textLabel?.text = arr[indexPath.row]
        return cell
    }
}