swift - 向 MKAnnotation 添加属性会出现 EXC_BAD_EXCESS 错误

Question

我正在尝试将我自己的属性添加到 MKAnnotation，但我这样做时出现错误。我想要完成的是除了 title 和 subtitle 之外添加例如 height 和 rate。

class MapPin: NSObject, MKAnnotation {
    var coordinate: CLLocationCoordinate2D
    var title: String
    var subtitle: String
    var imageName: String

    init(coordinate: CLLocationCoordinate2D, title: String, subtitle: String, imageName: String) {
        self.coordinate = coordinate
        self.title = title
        self.subtitle = subtitle
        self.imageName = imageName
    }
}

这就是我定义标记的方式:

    var request = NSURLRequest(URL: url!)
    var data = NSURLConnection.sendSynchronousRequest(request, returningResponse: nil, error: nil)
    if data != nil {
        var dataArray = JSON(data: data!)

        for (key, data) in dataArray {
            var title = data["name"]
            var subtitle = data["description"]
            var lat = data["lat"]
            var lng = data["lng"]

            var marker = CustomPointAnnotation()
            marker.coordinate = CLLocationCoordinate2D(latitude: lat.doubleValue, longitude: lng.doubleValue)
            marker.title = title.string
            marker.subtitle = subtitle.string
            marker.imageName = "marker.png"
            marker.image = "Test";
            mapView.addAnnotation(marker)
        }
    }

这是我尝试检索数据的地方:

func mapView(mapView: MKMapView!, annotationView view: MKAnnotationView!, calloutAccessoryControlTapped control: UIControl!) {
    println("Called")

    performSegueWithIdentifier("mapToCity", sender: self)
    var pinData = view.annotation as! MapPin  //EXC_BAD_ACCESS Error
    var title = pinData.title
    var subtitle = pinData.subtitle
    var lat = pinData.coordinate.latitude
    var lng = pinData.coordinate.longitude
    var image = pinData.imageName
    NSUserDefaults.standardUserDefaults().setObject(title, forKey: "title")
    NSUserDefaults.standardUserDefaults().setObject(subtitle, forKey: "subtitle")
    NSUserDefaults.standardUserDefaults().setObject(lat, forKey: "lat")
    NSUserDefaults.standardUserDefaults().setObject(lng, forKey: "lng")
}

当我尝试执行var pinData行时，我收到错误Thread 1: EXC_BAD_ACCESS (code =1, address=0x4)。这可能是什么原因以及如何解决？

Answer 1

首先，您需要检查您获得的注释类型:

func mapView(mapView: MKMapView!, annotationView view: MKAnnotationView!, calloutAccessoryControlTapped control: UIControl!) {
    println("Called")

    // Below condition is for custom annotation
    let MapPin= view.annotation as? MapPin
    println("Subtitle \(MapPin.subtitle)")
    performSegueWithIdentifier("mapToCity", sender: self)
    var title = MapPin.title
    var subtitle = MapPin.subtitle
    var lat = MapPin.coordinate.latitude
    var lng = MapPin.coordinate.longitude
    var image = MapPin.imageName
    NSUserDefaults.standardUserDefaults().setObject(title, forKey: "title")
    NSUserDefaults.standardUserDefaults().setObject(subtitle, forKey: "subtitle")
    NSUserDefaults.standardUserDefaults().setObject(lat, forKey: "lat")
    NSUserDefaults.standardUserDefaults().setObject(lng, forKey: "lng")
   }else{

    return nil
  }
}