向后导航时，搜索栏被隐藏

Question

我在主页上显示搜索栏。当我按下UIViewController然后返回首页时，搜索栏变为隐藏状态。 这是我的代码

func setupSearch(){
        searchController = UISearchController(searchResultsController: resultsTableController)

        searchController.searchResultsUpdater = self
        searchController.searchBar.autocapitalizationType = .none
        searchController.searchBar.searchTextField.placeholder = "Enter a search term...".localized()
        searchController.searchBar.returnKeyType = .search
        
        // Place the search bar in the navigation bar.
        navigationItem.searchController = searchController

        navigationItem.hidesSearchBarWhenScrolling = true
//        searchController.hidesNavigationBarDuringPresentation = false

        // Monitor when the search controller is presented and dismissed.
        searchController.delegate = self

        // Monitor when the search button is tapped, and start/end editing.
        searchController.searchBar.searchTextField.delegate = self

        /** Specify that this view controller determines how the search controller is presented.
            The search controller should be presented modally and match the physical size of this view controller.
        */
        definesPresentationContext = true
    }