使用从多个函数中检索到的JSON数据

Question

我从API检索了json数据（纬度和经度），我想在mapView中放置标记。效果很好，但是如果用户放大或缩小，我想更改标记。我找不到从多个函数使用数据的方法，或者我不知道在课堂上全局使用它。我尝试制作var listLocations = [Locations]() Array，但找不到获取数据的方法。

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    getLocations { (result) in
        switch result {
        case .success(let locations):
            locations.forEach({ (locations) in

                let lat = locations.location.latitude
                let lon = locations.location.longitude
                DispatchQueue.main.async{



                    let marker = GMSMarker()
                    marker.position = CLLocationCoordinate2DMake(lat, lon)
                    marker.map = self.mapView
                    let camera = GMSCameraPosition.camera(withLatitude: lat, longitude:lon, zoom:8)
                    self.mapView.animate(to: camera)


                }

            })
        case .failure(let error):
            print("Failed to load Locations", error)
        }
    }
    //let location = locations.last


    self.locationManager.stopUpdatingLocation()

}

来自API的请求

func getLocations(completion: @escaping(Result<[Locations], Error>) -> ()) {

    let urlString = "API URL HERE"
    guard let url = URL(string: urlString) else { return }

    URLSession.shared.dataTask(with: url) { (data, response, error) in
        if let error = error {
            completion(.failure(error))
            return
        }
        do {
            let locations = try JSONDecoder().decode([Locations].self, from: data!)
            completion(.success(locations))
        } catch let jsonError{
            completion(.failure(jsonError))
        }


    }.resume()
}

结构

    struct Locations: Codable {
    let id: Int
    let location: AreaElement
    let name: Name?
    let type: String
    let area: [AreaElement]?

    enum CodingKeys: String, CodingKey {
        case id = "ID"
        case location = "Location"
        case name = "Name"
        case type = "Type"
        case area = "Area"
    }

}
struct AreaElement: Codable {
    let latitude, longitude: Double

    enum CodingKeys: String, CodingKey {
        case latitude = "Latitude"
        case longitude = "Longitude"
    }
}

struct Name: Codable {
    let latin, local: String?

    enum CodingKeys: String, CodingKey {
        case latin = "Latin"
        case local = "Local"
    }
}

Answer 1

您需要保留对标记的引用（让marker = GMSMarker（））。您可以随时更改标记的位置。