Swift：自定义注释丢失字幕

如何解决Swift：自定义注释丢失字幕

我创建了一个自定义注释，然后将其放置在地图上。然后，当我选择它时，它不再具有字幕属性值，并且失去了info属性。

自定义注释：

import Foundation
import MapKit

class GAPoint: NSObject,MKAnnotation {
    var title: String?
    var subTitle: String?
    var coordinate: CLLocationCoordinate2D
    var info: String

    init(title: String,subTitle: String,coordinate: CLLocationCoordinate2D,info: String) {
        self.title = title
        self.subTitle = subTitle
        self.coordinate = coordinate
        self.info = info
    }
}

将其放在地图上：

var titles = ["title1","title2"]
var ids = ["id1","id2"]

for i in 0...1 {
    // Create Annotation Array
    let point = CLLocationCoordinate2D(latitude:
         fences[i].CENTER_LAT,longitude: fences[i].CENTER_LONG)
    //Now use this point to add annotation on map.
    let title = titles[i]
    let id = ids[i]
    let annotation = GAPoint(title: title,subTitle: id,coordinate: point,info: id)
    annotations.append(annotation)
}

// Add Annotation to map
self.mapView?.addAnnotations(annotations)

在添加注释时调用：

// Annotation View Properties (Pin Added or Moved) ---------------------
func mapView(_ mapView: MKMapView,viewFor annotation: MKAnnotation) -> MKAnnotationView? {
    print("mv viewFor Annotation: Pin Added or Moved")
    // If Annotation (Pin) is Not GAPoint Don't Add
    guard annotation is GAPoint else { return nil }
    if let identifier = annotation.title {
        var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: identifier!)
        if annotationView == nil {
            annotationView = MKPinAnnotationView(annotation: annotation,reuseIdentifier: identifier)
            //annotationView?.canShowCallout = true
            annotationView?.isDraggable = true
            // Create Label
            let annotationLabel = UILabel(frame: CGRect(x: -75,y: -8,width: 150,height: 20))
            annotationLabel.numberOfLines = 1
            annotationLabel.textAlignment = .center
            annotationLabel.font = UIFont(name: "Arial",size: 10)
            annotationLabel.text = identifier
            annotationLabel.backgroundColor = UIColor.white
            annotationLabel.layer.cornerRadius = 10
            annotationLabel.clipsToBounds = true
            annotationView?.addSubview(annotationLabel)
            //annotationView?.image = UIImage(named: "gaPin.png")
        } else {
            annotationView?.annotation = annotation
        }
        return annotationView
    } else {
        return nil
    }
}

在选择注释时调用： （这是缺少字幕值的地方 并且info属性已消失）

func mapView(_ mapView: MKMapView,didSelect view: MKAnnotationView) {
    print("mv didSelect view: Selected a pin")
    guard view.annotation is GAPoint else { return }
    if let annotation = view.annotation {
        if let title1 = annotation.title {
            if let title = title1 {
                print(title)
            }
        }
        if let stitle1 = annotation.subtitle {
            if let stitle = stitle1 {
                print(stitle)
            }
        }
    }
}

解决方法

我做了一些研究，然后尝试使用 以下代码：

let loc : GAPoint = annotation as! GAPoint

在委托人的上下文中：

func mapView(_ mapView: MKMapView,didSelect view: MKAnnotationView) {

        print("mv didSelect view: Selected a pin")
        guard view.annotation is GAPoint else { return }
        
        if let annotation = view.annotation {
            let loc : GAPoint = annotation as! GAPoint
            if let title1 = annotation.title {
                if let title = title1 {
                    print(title)
                }
            }
            if let stitle1 = annotation.subtitle {
                if let stitle = stitle1 {
                    print(stitle)
                }
            }
        }
    }