在带约束的UINavigationBar中添加UISearchBar

import UIKit

class ViewController: UIViewController, UISearchBarDelegate {
    private let searchBar = UISearchBar()

    override func viewDidLoad() {
        super.viewDidLoad()

        // 添加UINavigationBar
        let navigationBar = UINavigationBar()
        navigationBar.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(navigationBar)

        // 添加UISearchBar并设置约束
        searchBar.translatesAutoresizingMaskIntoConstraints = false
        searchBar.delegate = self
        navigationBar.addSubview(searchBar)

        NSLayoutConstraint.activate([
            navigationBar.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
            navigationBar.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            navigationBar.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            navigationBar.heightAnchor.constraint(equalToConstant: 44),

            searchBar.topAnchor.constraint(equalTo: navigationBar.topAnchor),
            searchBar.leadingAnchor.constraint(equalTo: navigationBar.leadingAnchor),
            searchBar.trailingAnchor.constraint(equalTo: navigationBar.trailingAnchor),
            searchBar.bottomAnchor.constraint(equalTo: navigationBar.bottomAnchor)
        ])
    }

    // UISearchBarDelegate方法
    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        // 处理搜索文本改变事件
        // 更新搜索结果
    }

    func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
        // 处理搜索按钮点击事件
        // 执行搜索操作
    }
}