searchDisplayController不显示searchBar

Question

我试图实现与日历应用程序类似的功能，到目前为止，我有下面的代码，当我点击leftBarButton时，只显示一个小的空白空间？为什么没有searchBar呢？ 我想要的是当你点击一个带有searchBar

的新导航栏时

当我点击searchButton时的插图：

代码：

override func viewDidLoad() {
    super.viewDidLoad()

    //searchBar
    theSearchBar = UISearchBar(frame: CGRectZero)
    theSearchBar?.delegate = self
    theSearchBar?.showsCancelButton = true
    theSearchBar?.placeholder = "Søg efter produkter"



    searchController = UISearchDisplayController(searchBar: theSearchBar!, contentsController: self)
    searchController?.delegate = self
    searchController?.searchResultsDelegate = self
    searchController?.searchResultsDataSource = self




}


@IBAction func showSearchBar(sender: UIBarButtonItem) {

    theSearchBar?.becomeFirstResponder()
    searchController?.setActive(true, animated: true)



}