如果未在viewDidLoad方法中设置，则不显示UISearchController

Question

我有一个显示不同子视图的视图控制器。每个子视图都是通过视图控制器调用var items = new List<(int id, string name)>(); 方法创建的，并且视图控制器将自身作为参数传递给该视图。

UINib()

一旦视图收到对其父视图控制器的引用，它将设置适当的导航栏

class func instanceFromNib(parentViewController: UIViewController) -> UIView {
    let view = UINib(nibName: "PodcastsPage", bundle: nil).instantiate(withOwner: nil, options: nil)[0] as! PodcastsPage
    view.viewController = parentViewController
    return view as UIView
}

在private var viewController: UIViewController! { didSet { setupNavigationBar() } } 内，我有一些代码应将setupNavigationBar()添加到视图控制器的导航栏中

UISearchController

虽然我运行应用程序时func setupNavigationBar() { guard let navigationBar = viewController.navigationController?.navigationBar else { return } navigationBar.isTranslucent = false navigationBar.barTintColor = .navigationBar navigationBar.titleTextAttributes = [ .font: UIFont(name: "AvenirNext-DemiBold", size: 18.0)!, .foregroundColor: UIColor.textPrimary ] viewController.navigationItem.title = "Follow Podcasts" let nextButton = UIBarButtonItem(title: "Finish", style: .done, target: nil, action: nil) nextButton.tintColor = .orangePrimary viewController.navigationItem.setRightBarButton(nextButton, animated: false) // Set UISearchController here // let searchController = UISearchController(searchResultsController: nil) searchController.searchBar.placeholder = "Search" searchController.searchResultsUpdater = self viewController.navigationItem.searchController = searchController viewController.navigationItem.hidesSearchBarWhenScrolling = false } 不可见

但是，如果我像这样将UISearchController设置在视图控制器的UISearchController内，则实际上存在搜索栏。

viewDidLoad

要从子视图设置override func viewDidLoad() { super.viewDidLoad() let searchController = UISearchController(searchResultsController: nil) searchController.searchBar.placeholder = "Search" navigationItem.searchController = searchController navigationItem.hidesSearchBarWhenScrolling = false } ，我该怎么做？