iOS Swift MKLocalSearchRequest

Question

我正在开发一个应用程序，允许用户通过UIMapKit更新他们的位置。视图显示正确，但是当我选择UI Button "Find“时，应用程序会冻结以下消息：

在__ObjC.MKLocalSearchRequest的InfoViewController.swift上键入元数据访问器。“

我的UIOutlet链接到我的按钮，但是我的问题似乎集中在下面的代码上：

var appDelegate: AppDelegate!
var latitude: Double = 0.00
var longitude: Double = 0.00
var addLocation = addLocationDelegate()

var indicator = Indicator()

@IBOutlet var locationText: UITextField!


@IBAction func findOTMButton(_ sender: Any) {
    self.indicator.loadingView(true)

    let localSearchRequest = MKLocalSearchRequest()
    localSearchRequest.naturalLanguageQuery = locationText.text
    let localSearch = MKLocalSearch(request: localSearchRequest)
    localSearch.start { (localSearchResponse, error) -> Void in
        if localSearchResponse == nil{
            UdacityNetwork.sharedInstance().alertError(self, error: self.appDelegate.errorMessage.MapError)
            self.indicator.loadingView(false)
            return
        }

        let pointAnnotation = MKPointAnnotation()
        pointAnnotation.title = self.locationText.text!
        pointAnnotation.coordinate = CLLocationCoordinate2D(latitude: localSearchResponse!.boundingRegion.center.latitude, longitude:     localSearchResponse!.boundingRegion.center.longitude)

        self.latitude = localSearchResponse!.boundingRegion.center.latitude
        self.longitude = localSearchResponse!.boundingRegion.center.longitude

        let controller = self.storyboard!.instantiateViewController(withIdentifier: "LinkViewController") as! LinkViewController
        controller.location = self.locationText.text!
        controller.pointAnnotation = pointAnnotation
        controller.latitude = self.latitude
        controller.longitude = self.longitude
        self.indicator.loadingView(false)
        self.present(controller, animated: true, completion: nil)
    }

Answer 1

您应该回到主线程更新UI。

localSearch.start { (localSearchResponse, error) -> Void in
        DispatchQueue.main.async {
            // Update the UI
            ....
        }
}