范围按钮隐藏在iOS 11的搜索栏下

Question

我的应用程序中有一个搜索控制器，根据iOS 11上的苹果文档，必须将其添加到navigationItem的searchController属性中。我还有一些searchController的范围按钮。一切正常，但是当我将设备旋转到横向并旋转回肖像时，就会发生有线的事情。范围按钮隐藏在搜索字段下。如果我按下取消按钮并再次点击搜索字段，则会返回正常状态。该错误仅在iOS 11上每次都会重现。搜索栏将如下所示：

搜索控制器的正常状态：

这就是我添加searchController的方式：

    searchController.searchResultsUpdater = self as UISearchResultsUpdating
    searchController.dimsBackgroundDuringPresentation = false
    definesPresentationContext = true

    searchController.hidesNavigationBarDuringPresentation = false
    searchController.searchBar.tintColor = UIColor.black
    searchController.searchBar.sizeToFit()
    searchController.searchBar.placeholder = "Search device"
    searchController.searchBar.scopeButtonTitles = ["Device", "Person", "OS version", "Serial"]

    if #available(iOS 11.0, *) {
        self.navigationItem.searchController = self.searchController
        self.navigationItem.hidesSearchBarWhenScrolling = false

        if let textField = searchController.searchBar.value(forKey: "searchField") as? UITextField {
            if let backgroundView = textField.subviews.first {
                backgroundView.backgroundColor = UIColor.white
                backgroundView.layer.cornerRadius = 10
                backgroundView.clipsToBounds = true
            }
        }
    } else {
        tableView.tableHeaderView = searchController.searchBar
    }
    searchController.searchBar.delegate = self as UISearchBarDelegate