swift - Swift 中的函数错误处理

Question

我正在我的 CoreLocation 和基于 MapKit frimeworks 的应用程序中实现本地搜索。我正在关注这个 Tutorial

我收到以下错误:

Cannot convert value of type '(MKLocalSearchResponse!, NSError!) -> ()' to expected argument type 'MKLocalSearchCompletionHandler' (aka '(Optional, Optional) -> ()')

这是我的代码:

import UIKit
import CoreLocation
import MapKit


class ViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate{
    private let LocationManager = CLLocationManager()
    let request = MKLocalSearchRequest()
    private var previousPoint:CLLocation?
    private var totalMovementDistance:CLLocationDistance = 0




    @IBOutlet var mapView: MKMapView!


    @IBOutlet var searchText: UITextField!
    var matchingItems: [MKMapItem] = [MKMapItem]()

    @IBAction func textFieldReturn(sender:AnyObject) {
        sender.resignFirstResponder()
        mapView.removeAnnotations(mapView.annotations)
        self.performSearch()

    }

    @IBOutlet var latitudeLabel: UILabel!
    @IBOutlet var longitudeLabel: UILabel!
    @IBOutlet var horizontalAccuracy: UILabel!
    @IBOutlet var altitudeLabel: UILabel!
    @IBOutlet var verticalAccuracyLabel: UILabel!
    @IBOutlet var distanceTraveledLabel: UILabel!






    override func viewDidLoad() {
        super.viewDidLoad()
        LocationManager.delegate = self
        LocationManager.desiredAccuracy = kCLLocationAccuracyBest
        LocationManager.requestWhenInUseAuthorization()



        // Do any additional setup after loading the view, typically from a nib.
    }



    func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
        print("Authorization Status Changed to \(status.rawValue)")
        switch status {
        case .Authorized, .AuthorizedWhenInUse:
            LocationManager.startUpdatingLocation()
            mapView.showsUserLocation = true

        default:
            LocationManager.stopUpdatingLocation()
            mapView.showsUserLocation = false
        }
    }

    func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
        let errorType = error.code == CLError.Denied.rawValue ? "Access Denied": "Error \(error.code)"
        let alertController = UIAlertController(title: "Location Manager Error", message: errorType, preferredStyle: .Alert)
        let okAction = UIAlertAction(title: "OK", style: .Cancel, handler: {action in})
        alertController.addAction(okAction)
        presentViewController(alertController, animated: true, completion: nil)
    }

    func performSearch() {

        matchingItems.removeAll()
        let request = MKLocalSearchRequest()
        request.naturalLanguageQuery = searchText.text
        request.region = mapView.region

        let search = MKLocalSearch(request: request)

        search.startWithCompletionHandler { (localResponse:MKLocalSearchResponse?, error: NSError?) -> Void in


            if error != nil {
                print("Error occured in search: \(error?.localizedDescription)")
            } else if localResponse == 0 {
                print("No matches found")
            } else {
                print("Matches found")

                for item in localResponse.mapItems  {
                    print("Name = \(item.name)")
                    print("Phone = \(item.phoneNumber)")

                    self.matchingItems.append(item as MKMapItem)
                    print("Matching items = \(self.matchingItems.count)")

                    var annotation = MKPointAnnotation()
                    annotation.coordinate = item.placemark.coordinate
                    annotation.title = item.name
                    self.mapView.addAnnotation(annotation)
                }
            }
        }
    }


    func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        let newLocation = (locations as [CLLocation]) [locations.count - 1]

        let latitudeString = String(format: "%g\u{00B0}", newLocation.coordinate.latitude)
        latitudeLabel.text = latitudeString

        let longitudeString = String(format: "%g\u{00B0}", newLocation.coordinate.longitude)
        longitudeLabel.text = longitudeString

        let horizontalAccuracyString = String(format: "%gm", newLocation.horizontalAccuracy)
        horizontalAccuracy.text = horizontalAccuracyString

        let altitudeString = String(format: "%gm", newLocation.altitude)
        altitudeLabel.text = altitudeString

        let verticalAccuracyString = String(format: "%gm", newLocation.verticalAccuracy)
        verticalAccuracyLabel.text = verticalAccuracyString

        if newLocation.horizontalAccuracy < 0 {
            //invalid accuracy
            return

        }


        if newLocation.horizontalAccuracy > 100 ||
            newLocation.verticalAccuracy > 50 {
                return
        }

        if previousPoint == nil {
            totalMovementDistance = 0
            let start = Place(title:"Strating Point", subtitle:"This is where we started", coordinate:newLocation.coordinate)
            mapView.addAnnotation(start)
            let region = MKCoordinateRegionMakeWithDistance(newLocation.coordinate, 100, 100)
            mapView.setRegion(region, animated:true)


        }else {
            print("movement distance: \(newLocation.distanceFromLocation(previousPoint!))")
            totalMovementDistance += newLocation.distanceFromLocation(previousPoint!)

        }

        previousPoint = newLocation

        let distanceString = String(format: "%gm", totalMovementDistance)
        distanceTraveledLabel.text = distanceString



    }



}

错误在这一行:

search.startWithCompletionHandler({(response:
            MKLocalSearchResponse!,

编辑:

Answer 1

替换!在与？ (因为那是方法的签名)示例:

    search.startWithCompletionHandler { (localResponse:MKLocalSearchResponse?, error:NSError?) -> Void in

    }