iOS：MapView 注释未显示图钉

由于某些奇怪的原因，viewForAnnotation 仅适用于 viewDidLoad 中设置的引脚（这是一个测试引脚）。在其他地方加载的引脚在按下时不会被注释。我已经设置了代表。我认为这与mapView调用中的标识符有关？但我不确定如何解决它。任何帮助表示赞赏！谢谢！

这是我的代码：

import Foundation
import UIKit
import MapKit
import CoreLocation
import Alamofire

class MapViewController: UIViewController, MKMapViewDelegate {

var locationManager:CLLocationManager = CLLocationManager()


@IBOutlet weak var potholeMapView: MKMapView!

var listData: Array<String> = []
var idData: Array<Int> = []
var descriptionData: Array<String> = []

var latitudeData:Array<Double> = []
var longitudeData:Array<Double> = []

override func viewDidLoad() {
    super.viewDidLoad()
    potholeMapView.delegate = self
    locationManager.requestWhenInUseAuthorization()
    potholeMapView!.region = sanDiegoCountyLocation()
    potholeMapView!.mapType = MKMapType.Standard
    potholeMapView!.showsUserLocation = true
    potholeMapView!.showsTraffic = true
    print(potholeMapView!.userLocationVisible)

    // WORKING HERE ACCESSORY VIEW SHOWS
    let encinitas = CLLocationCoordinate2DMake(32.955, -117.2459)
    let marker = AnnotatedLocation(
        coordinate: encinitas,
        title: "There",
        subtitle: "You are not here")
    potholeMapView!.addAnnotation(marker)

}

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    //HERE ACCESSORY VIEWS DONT SHOW
    loadPotholeData()
}


func sanDiegoCountyLocation()-> MKCoordinateRegion {
    let center = CLLocationCoordinate2DMake(32.76572795, -117.07319880 )
    let widthMeters:CLLocationDistance = 100
    let heightMeters:CLLocationDistance = 1000*120
    return MKCoordinateRegionMakeWithDistance(center, widthMeters, heightMeters)
}

func loadPotholeData(){
    let url = "http://bismarck.sdsu.edu/city/fromDate"
    let parametersGet = ["type" : "street", "user" : "008812"]
    Alamofire.request(.GET, url, parameters: parametersGet)
        .responseJSON { response in
            if let dataGet = response.result.value {
                let dataDict:NSArray = dataGet as! NSArray
                for item in dataDict{
                    let descrip = item["created"]
                    self.listData.append(descrip!! as! String)
                    let ids = item["id"]
                    self.idData.append(ids! as! Int)
                    let description = item["description"]
                    self.descriptionData.append(description!! as! String)
                    let latitude = item["latitude"]
                    self.latitudeData.append(latitude as! Double)
                    let longitude = item["longitude"]
                    self.longitudeData.append(longitude as! Double)
                }
            }
            else {
                print("There was some error getting data")
            }
    }
    createAllPins()
}

func createAllPins(){
    for (x, y) in zip(self.latitudeData, self.longitudeData) {
        let location = CLLocationCoordinate2DMake(x, y)
        let marker = AnnotatedLocation(
            coordinate: location,
            title: "",
            subtitle: "")
        potholeMapView!.addAnnotation(marker)
    }
}

func mapView(mapView: MKMapView, viewForAnnotation annotation: MKAnnotation) -> MKAnnotationView? {
    if let annotation = annotation as? AnnotatedLocation {
        let identifier = "pin"
        var view: MKPinAnnotationView
        if let dequeuedView = mapView.dequeueReusableAnnotationViewWithIdentifier(identifier)
            as? MKPinAnnotationView {
                dequeuedView.annotation = annotation
                view = dequeuedView
        } else {
            view = MKPinAnnotationView(annotation: annotation, reuseIdentifier: identifier)
            //view = MKPinAnnotationView(annotation: <#T##MKAnnotation?#>, reuseIdentifier: <#T##String?#>)
            view.canShowCallout = true
            view.calloutOffset = CGPoint(x: -5, y: 5)
            view.rightCalloutAccessoryView = UIButton(type: .DetailDisclosure)
        }
        return view
    }
    return nil
}


func mapView(mapView: MKMapView, annotationView view: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {
    self.performSegueWithIdentifier("pushAnnotation", sender: view)
}

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    if let identifier = segue.identifier {
        switch identifier {
            case "pushAnnotation":
                let nextVC = segue.destinationViewController as! MapAnnotationDetailViewController
                //nextVC.
            default: break
        }
    }
}

}

看来这是因为你的标题和其他人的副标题是空白的。我测试了引号中没有任何内容并添加了一些内容，这似乎解决了这个问题。