如何使用代码将 UISearchController Searchbar 放到导航栏上

Question

如果我将 ViewController 嵌入到导航栏中，navigationItem.titleView.resultSearchController?.searchBar 将在导航栏中放置一个搜索栏。但是，我用代码创建了一个 UISearchController 和一个 UINavigationBar。这一次，navBar 出现了，但 searchBar 没有出现。

resultSearchController = UISearchController(searchResultsController: locationSearchTable)
resultSearchController?.searchResultsUpdater = locationSearchTable

let searchBar = resultSearchController!.searchBar
searchBar.sizeToFit()
searchBar.delegate = self

let navBar: UINavigationBar = UINavigationBar(frame: CGRect(x: 0, y:0, width: 375, height: 64))
self.view.addSubview(navBar)
//navBar.topItem = resultSearchController?.searchBar
self.navigationItem.titleView = resultSearchController?.searchBar

navBar.topItem = resultSearchController?.searchBar 不起作用，因为topItem 是一个字符串值，而resultSearchController?.searchBar 是一个UIView 类型。怎样才能达到同样的效果？

Answer 1

创建一个UINavigationItem 实例并将其添加到创建的导航栏。 将搜索控制器搜索栏添加到 UINavigationItem 作为titleView。

class SearchViewController: UIViewController, UISearchControllerDelegate, UISearchResultsUpdating, UISearchBarDelegate {

    var searchController: UISearchController!

    override func viewDidLoad() {
        super.viewDidLoad()
        self.addNavigationbar()
    }

    func addNavigationbar() {
        let navBar = UINavigationBar(frame: CGRect(x: 0, y: 0, width: self.view.frame.size.width, height: 60))
        self.view.addSubview(navBar)

        let navigationItem = UINavigationItem(title: "")
        self.searchController = searchControllerWith(searchResultsController: nil)
        navigationItem.titleView = self.searchController.searchBar

        navBar.setItems([navigationItem], animated: false)
        self.definesPresentationContext = true
    }

    func searchControllerWith(searchResultsController: UIViewController?) -> UISearchController {

        let searchController = UISearchController(searchResultsController: searchResultsController)
        searchController.delegate = self
        searchController.searchResultsUpdater = self
        searchController.searchBar.delegate = self
        searchController.hidesNavigationBarDuringPresentation = false
        searchController.dimsBackgroundDuringPresentation = true

        return searchController
    }

Answer 2

class UIViewController: UIViewController, UISearchControllerDelegate, UISearchResultsUpdating, UISearchBarDelegate {

    var searchController : UISearchController!

    override func viewDidLoad() {
        super.viewDidLoad()

        self.searchController = UISearchController(searchResultsController:  nil)

        self.searchController.searchResultsUpdater = self
        self.searchController.delegate = self
        self.searchController.searchBar.delegate = self

        self.searchController.hidesNavigationBarDuringPresentation = false
        self.searchController.dimsBackgroundDuringPresentation = true

        self.navigationItem.titleView = searchController.searchBar

        self.definesPresentationContext = true
    }

    func updateSearchResults(for searchController: UISearchController) {

    }


}