Question

我需要从Firebase中按值使用不同颜色的注释，所以我创建了一个类：

class AnnotationClass : MKPointAnnotation {
    var parametro: String?
    var titolo:String?
    var sottotitolo: String?
    var tipo: String?

}

然后设置它：

let annotation = AnnotationClass()
                    annotation.titolo = location.citta?.uppercased() as? String
                    annotation.sottotitolo = "\(location.titolo!) POSTI"
                    annotation.parametro = "\(location.id!)"
                    annotation.tipo = "\(location.tipo!)"
                    annotation.title = "\(location.tipo!)"

这里的主要内容是如何在下一个函数中获取它？如果commentView？.annotation？.tipo ==“ CONCORSO” 错误：“ MKAnnotation”类型的值没有成员“ tipo”

func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {



        var annotationView: MKMarkerAnnotationView? = mapView.dequeueReusableAnnotationView(withIdentifier: "mia2") as? MKMarkerAnnotationView
        annotationView = MKMarkerAnnotationView(annotation: annotation, reuseIdentifier: "mia2")

        if annotationView?.annotation?.tipo == "CONCORSO" {
             annotationView?.markerTintColor = #colorLiteral(red: 0.2392156869, green: 0.6745098233, blue: 0.9686274529, alpha: 1)
            annotationView?.glyphText = "C"
        } else {

            annotationView?.markerTintColor = #colorLiteral(red: 0.9254901961, green: 0.2352941176, blue: 0.1019607843, alpha: 1)
            annotationView?.glyphText = "A"
        }

        return annotationView

    }

Answer 1

您需要将annotation: MKAnnotation强制转换为自定义类：

let myCustomAnnotation = annotation as? AnnotationClass

以下，我已修复了您的委托方法中的多个问题

func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {

    var annotationView: MKMarkerAnnotationView! = mapView.dequeueReusableAnnotationView(withIdentifier: "mia2") as? MKMarkerAnnotationView

    if (annotationView == nil) {
        // Create a new annotation view
        annotationView = MKMarkerAnnotationView(annotation: annotation, reuseIdentifier: "mia2")
    } else {
        // update existing (reusable) annotationView's annotation
        annotationView.annotation = annotation
    }

    if let myCustomAnnotation = annotation as? AnnotationClass, myCustomAnnotation.tipo == "CONCORSO" {
        annotationView.markerTintColor = #colorLiteral(red: 0.2392156869, green: 0.6745098233, blue: 0.9686274529, alpha: 1)
        annotationView.glyphText = "C"
    } else {
        annotationView.markerTintColor = #colorLiteral(red: 0.9254901961, green: 0.2352941176, blue: 0.1019607843, alpha: 1)
        annotationView.glyphText = "A"
    }

    return annotationView
}

您还可以将if语句缩短为：

if (annotation as? AnnotationClass)?.tipo == "CONCORSO" {
    ...
}

类型“ MKAnnotation”的值没有成员“ tipo”

1 个答案: