拖动自定义注释视图

Question

我有我的 CoreData 自定义 Annotation class:

extension Annotation: MKAnnotation {

    public var coordinate: CLLocationCoordinate2D {
        let cllCoordinate = CLLocationCoordinate2D(latitude: self.latitude, longitude: self.longitude)
        return cllCoordinate
    }

    public var title: String? {
        return self.objectId
    }

    class func keyPathsForValuesAffectingCoordinate() -> Set<String> {
        return Set<String>([ #keyPath(latitude), #keyPath(longitude) ])
    }

    @nonobjc public class func fetchRequest() -> NSFetchRequest<Annotation> {
        return NSFetchRequest<Annotation>(entityName: "Annotation")
    }

    @NSManaged public var latitude: Double
    @NSManaged public var longitude: Double
    @NSManaged public var dateTime: Date
    @NSManaged public var type: String
    @NSManaged public var objectId: String?

}

结合 fetchedResultsController 添加和删除注释效果很好。但是现在想把一个注解拖到另一个位置。但仅将 isDraggable 设置为 true 并不是全部。我找不到更新的描述如何将其集成。

这是我的 viewFor 方法：

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

    guard annotation is Annotation else { return nil }

    let identifier = "Annotation"
    var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: identifier)

    if annotationView == nil {
        annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: identifier)
        annotationView?.isDraggable = true
        annotationView?.canShowCallout = true
    } else {
        annotationView!.annotation = annotation
    }

    let customAnno = annotation as! Annotation
    let image = UIImage(named: customAnno.type)
    annotationView!.image = image

    return annotationView
}

我还需要什么？我想按住注释，按住并转到另一个位置，然后松开手指，注释就停留在那里。

Answer 1

拖动时，需要改变底层注解的coordinate。如果它是只读的，它就不能这样做。所以，如果你想让它可以拖动，你必须给 coordinate 属性一个 setter:

public var coordinate: CLLocationCoordinate2D {
    get {
        CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
    }
    set {
        latitude = newValue.latitude
        longitude = newValue.longitude
    }
}

拖动自定义注释视图

Drag Custom Annotation View

swift

mkmapview

draggable

mkannotation

mkannotationview