如何更改 UISearchController 中搜索文本字段的背景颜色？

更改 UISeachController 中文本字段背景颜色的代码示例：

class ViewController: UIViewController {

    let searchController = UISearchController(searchResultsController: nil)

    private lazy var searchTextField: UITextField? = { [unowned self] in
        var textField: UITextField?
        searchController.searchBar.subviews.forEach({ view in
            view.subviews.forEach({ view in
                if let view  = view as? UITextField {
                    textField = view
                }
            })
        })
        return textField
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        searchController.obscuresBackgroundDuringPresentation = false
        searchController.searchBar.placeholder = "Search Candies"
        navigationItem.searchController = searchController
        definesPresentationContext = true

        if let bg = self.searchTextField?.subviews.first {
            bg.backgroundColor = .green
            bg.layer.cornerRadius = 10
            bg.clipsToBounds = true
        }
    }
}

结果：

尝试这样的自定义UISearchBar：

func configureSearchBar() {
        searchBar.layer.borderWidth = 0
        searchBar.backgroundColor = UIColor.white
        searchBar.backgroundImage = UIImage()
        searchBar.barTintColor = UIColor.white

        if let textField = self.searchBar.value(forKey: "searchField") as? UITextField {
            textField.font = UIFont.systemFont(ofSize: 23, weight: UIFont.Weight.light)
            textField.textColor = UIColor(withHex: 0x000000)
            textField.borderStyle = .none
            textField.leftViewMode = .never
            textField.textAlignment = .left

            if let clearButton = textField.value(forKey: "clearButton") as? UIButton {
                clearButton.setImage(UIImage(named: "searchClearIco")!, for: .normal)
                clearButton.setImage(UIImage(named: "searchClearIcoTap")!, for: .highlighted)
            }
        }
 }