点击后搜索栏消失

我正在尝试使用Google Maps搜索附近的地方。下面是我到目前为止所做的代码

 override func viewDidLoad() {
    super.viewDidLoad()
//Adding Mapview
    mapView  = GMSMapView(frame: CGRectMake(0, 120, self.view.bounds.width, self.view.bounds.height - 120))

    self.view.addSubview(mapView)
    mapView.mapType = kGMSTypeNormal

    locationManager.delegate = self
    locationManager.requestWhenInUseAuthorization()

    let resultTableView = UITableView(frame: CGRectMake(10, 100, 300, 60))
    self.searchResultController = UITableViewController()
    self.searchResultController?.tableView = resultTableView
    self.searchResultController?.tableView.dataSource = self
    self.searchResultController?.tableView.delegate = self

      self.searchResultController?.tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")
    self.searchController = UISearchController(searchResultsController: self.searchResultController)
    self.searchController?.searchResultsUpdater = self
    self.searchController?.hidesNavigationBarDuringPresentation = true
    self.searchController?.dimsBackgroundDuringPresentation = false
    self.searchController?.delegate = self
    self.searchController?.searchBar.frame = CGRectMake(0,70,self.view.bounds.width,40)
    self.searchController?.searchBar.placeholder = "Please choose a location"
    self.view.addSubview(self.searchController!.searchBar)
    self.definesPresentationContext = true
}

一切正常，但一次单击后searcg条消失。但是它确实起作用。