如何将自定义属性从MAPBOX注释传递到其标注视图

Question

i子分类 MGLAnnotation添加额外的属性 var tags so：

class MasterMapAnnotation: NSObject, MGLAnnotation {
    var coordinate: CLLocationCoordinate2D
    var title: String?
    var subtitle: String?
    var tags: String?
    init(coordinate: CLLocationCoordinate2D, title: String?, subtitle: String?, tags: String?) {
        self.coordinate = coordinate
        self.title = title
        self.subtitle = subtitle
        self.tags = tags
    }
}

这是传递到地图的注释：

let annotation = MasterMapAnnotation(coordinate: CLLocationCoordinate2D(latitude: 50.0, longitude: 50.0), title: "Numero Uno", subtitle: "Numero Uno subtitle", tags: "#tag1 #tag2")
mapView.addAnnotation(annotation)

MapView代表调用自定义标注视图：

func mapView(_ mapView: MGLMapView, calloutViewFor annotation: MGLAnnotation) -> MGLCalloutView? {
    return MasterMapCalloutView(representedObject: annotation)
}

因此，在"标注"视图子类（下图）中，如何访问此新属性tags？

class MasterMapCalloutView: UIView, MGLCalloutView {
    var representedObject: MGLAnnotation
    let dismissesAutomatically: Bool = false
    let isAnchoredToAnnotation: Bool = true
    lazy var leftAccessoryView = UIView()
    lazy var rightAccessoryView = UIView()
    weak var delegate: MGLCalloutViewDelegate?
    required init(representedObject: MGLAnnotation) {
        self.representedObject = representedObject
        super.init(frame: .zero)
    }
    required init?(coder decoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    // callout view delegate: present callout
    func presentCallout(from rect: CGRect, in view: UIView, constrainedTo constrainedView: UIView, animated: Bool) {
        if !representedObject.responds(to: #selector(getter: MGLAnnotation.title)) {
            return
        }
        view.addSubview(self)
        let title = representedObject.title
        let tags = representedObject.tags // how to access this?
    }
}

问题很明显是，子类（MasterMapAnnotation）具有自定义tags属性，而不是其超级类（MGLAnnotation），但我不知道该如何（a）将ArdectedObject设置为MasterMapAnnotation或（b）简单地访问MasterMapAnnotation自定义属性重新配置协议。

Answer 1

我可能缺少某些东西，但是您肯定会检查是否可以将MGlannotation对象施放为Mastermapannotation：

guard let masterAnnotation : MasterMapAnnotation = representedObject as? MasterMapAnnotation else { return }
let tags : String? = masterAnnotation.tags
// etc

显然，除使用警卫以外，还有其他控制流程的方法，但我希望您能得到要点。