使用searchBar时隐藏后退按钮

我的NavigationBar中有一个SearchBar . 单击SearchBar时，它应显示在导航栏上的“后退”按钮上 .

Link to what I want to achieve

所以我想隐藏后面的按钮，如上图所示，但我没有实现搜索栏与后退按钮重叠 . 谁能请帮忙

这是我的代码：

class FirstSearchTableViewController: UITableViewController, UISearchResultsUpdating {


let searchData = []
var filteredSearchData = [String]()
var resultSearchController = UISearchController()


override func viewDidLoad() {
    super.viewDidLoad()

    self.resultSearchController = ({
        let controller = UISearchController(searchResultsController: nil)
        controller.searchResultsUpdater = self
        controller.dimsBackgroundDuringPresentation = false
        controller.searchBar.placeholder = "Search for persons"
        controller.searchBar.sizeToFit()
        controller.searchBar.searchBarStyle = UISearchBarStyle.Minimal
        controller.searchBar.setValue("X", forKey: "_cancelButtonText")

        (UIBarButtonItem.appearanceWhenContainedInInstancesOfClasses([UISearchBar.self])).tintColor = UIColor.grayColor()


        self.navigationItem.titleView = controller.searchBar

        controller.hidesNavigationBarDuringPresentation = false


        return controller
    })()

    // Reload the table
    self.tableView.reloadData()


    self.tableView.backgroundColor = UIColor(red: 14/255.0, green: 23/255.0, blue: 38/255.0, alpha: 1)

    self.tableView.separatorColor = UIColor(red: 60/255.0, green: 69/255.0, blue: 83/255.0, alpha: 1)

    self.tableView.rowHeight = 80.0

    self.navigationController?.navigationBar.topItem?.title = ""
}

override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    // 1 
    // Return the number of sections.
    return 1
}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // 2
    if (self.resultSearchController.active) {
        return self.filteredSearchData.count
    }
    else {
        return self.searchData.count
    }
}


override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)

    // 3
    if (self.resultSearchController.active) {
        cell.textLabel?.text = filteredSearchData[indexPath.row]

        return cell
    }
    else {
        cell.textLabel?.text = searchData[indexPath.row] as? String

        return cell
    }
}


func updateSearchResultsForSearchController(searchController: UISearchController)
{
    filteredSearchData.removeAll(keepCapacity: false)

    let searchPredicate = NSPredicate(format: "SELF CONTAINS[c] %@", searchController.searchBar.text!)
    let array = (searchData as NSArray).filteredArrayUsingPredicate(searchPredicate)
    filteredSearchData = array as! [String]

    self.tableView.reloadData()
}

}