当我点击搜索图标时，我切换了另一个页面并将搜索栏添加到导航栏中，但切换之后，导航栏的顶部变成了黑色。

塞盖之前:

塞格之后:

class SearchViewController: UIViewController, UISearchBarDelegate {

    let searchController = UISearchController(searchResultsController: nil)
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        setupSearch()                    
    }
        
    func setupSearch() {
        searchController.searchBar.backgroundColor = #colorLiteral(red: 0.1333333333, green: 0.1333333333, blue: 0.1333333333, alpha: 1)
        navigationController?.navigationBar.backgroundColor = #colorLiteral(red: 0.1333333333, green: 0.1333333333, blue: 0.1333333333, alpha: 1)
        navigationItem.searchController = searchController
        UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self]).defaultTextAttributes = [NSAttributedString.Key.foregroundColor: UIColor.white]
        searchController.searchBar.delegate = self
    }
}