swift - 通过 rightCalloutAccessoryView 访问自定义 MKAnnotation 数据时出现问题

Question

当由 rightCalloutAccessoryView 触发时，我正在尝试访问我在自定义注释数据中设置的一些自定义数据。我收到如下所述的编译器错误。这是我的自定义 MKAnnotation，带有几个额外的变量 - status 和 supplierdataindex

class CustomMapPinAnnotation : NSObject, MKAnnotation {
  var coordinate: CLLocationCoordinate2D
  var title: String
  var subtitle: String
  var status: Int             
  var supplierdataindex: Int  

  init(coordinate: CLLocationCoordinate2D, title: String, subtitle: String, status: Int, supplierdataindex: Int) {
    self.coordinate = coordinate
    self.title = title
    self.subtitle = subtitle
    self.status = status
    self.supplierdataindex = supplierdataindex     
  }
}  // CustomMapPinAnnotation

var myCustomMapPinAnnotationArray = [CustomMapPinAnnotation] ()
// I build an array and put that into myCustomMapPinAnnotationArray
...
// I add the annotations initially in viewDidLoad in the ViewController.swift via this call  
theMapView.addAnnotations(myCustomMapPinAnnotationArray)

就 map 和图钉而言，一切都很好，但现在我想访问 myCustomMapPinAnnotation 数组的自定义部分，特别是“状态”和“供应商数据索引”这将插入更详细 View 的决策。我正在使用 calloutAccessoryControlTapped 来捕捉点击。

问题是这个编译器在下面给我一个错误，我尝试设置访问权限，我认为这会让我指向我认为应该内置到注释数据中的自定义数据。

“MKAnnotation”不能转换为“CustomMapPinAnnotation”

func mapView(mapView: MKMapView!, annotationView: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {

    if control == annotationView.rightCalloutAccessoryView {
        // This works and prints the data
        println("Right Callout was pressed and title = \(annotationView.annotation.title)")

        // This line yields a compiler error of: 'MKAnnotation is not convertible to 'CustomMapPinAnnotation'
        var pinannotation : CustomMapPinAnnotation = annotationView.annotation

        println("status was = \(myannotation.status)")
        println("supplierdataindex was = \(myannotation.supplierdataindex)")     
    }
}

Answer 1

您必须像这样将其类型转换为 CustomMapPinAnnotation，

func mapView(mapView: MKMapView!, annotationView: MKAnnotationView, calloutAccessoryControlTapped control: UIControl) {

    if control == annotationView.rightCalloutAccessoryView {

        if let pinannotation = annotationView.annotation as? CustomMapPinAnnotation{

          println("status was = \(pinannotation.status)")
          println("supplierdataindex was = \(pinannotation.supplierdataindex)")    

       }
    }
}