Question

我想访问我编写的父注释类的属性以检查它的值。

Annotation.swift

enum AnnotationType: Int {
    case AnnotationDefault = 0
    case AnnotationAED
    case AnnotationResponder
    case AnnotationIncident
}

class Annotation: NSObject, MKAnnotation {

    var coordinate: CLLocationCoordinate2D
    var title: String?
    var subTitle: String
    var type: AnnotationType

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

    func getType() -> AnnotationType {
        return self.type
    }
}

AEDAnnotation.swift

class AEDAnnotation : Annotation {
    let aed: AED

    init(aed: AED) {
        self.aed = aed
        super.init(coordinate: aed.coordinate, title: aed.street, subTitle: aed.owner, type: aed.annotationType)
    }

    func getAnnotationType() -> AnnotationType {
        return super.getType()
    }
}

我创建了一个这样的注释：

let annotation = AEDAnnotation.init(aed: aed)
self.annotationArray.append(annotation)

如果我遍历数组，我看到那里有有效的AEDAnnotations。但是为什么我无法访问我要求的Annotation.swift的基础属性。

for item in self.annotationArray {
    print(item.getType)
}

这不起作用。但是，如何才能访问type

的属性Annotation.swift

我得到的错误信息是： Value of type 'MKAnnotation' has no member 'getType'

Answer 1

该错误表示item属于MKAnnnotation类型。如果您想将其视为不同的类型，则需要将其强制转换。请尝试以下方法：

for item in self.annotationArray {
    if let myAnnotation = item as Annotation {
        print("\(myAnnotation.getType().rawValue)")
    }
    else {
        print("Annotation was not an Annotation type")
    }
}

访问父属性

1 个答案: