Question

我需要找到当前位置附近最近的城市。你能告诉我如何在我的项目中将坐标填充到一个数组中，以及如何计算我的位置和我周围最近的位置之间的距离。我必须以（KM）和城市名称显示距离，以便用户可以选择最适合他的城市。我还需要从json文件中调用代码中的坐标和名称我的JSON文件是：

 {
"City A": {
    "Position": {
        "Longitude": 9.96233,
        "Latitude": 49.80404
    }
},
"City B": {
    "Position": {
        "Longitude": 6.11499,
        "Latitude": 50.76891
    }
},
"City C": {
    "Position": {
        "Longitude": 6.80592,
        "Latitude": 51.53548
    }

到目前为止

和我的功能：

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

    let userlocation:CLLocation = locations[0] as CLLocation

    manager.stopUpdatingLocation()

    let location = CLLocationCoordinate2D(latitude: userlocation.coordinate.latitude, longitude: userlocation.coordinate.longitude)

    let span = MKCoordinateSpanMake(0.5, 0.5)

    let region = MKCoordinateRegion(center: location, span: span)

    Mapview.setRegion(region, animated: true)
    let locations = ["42.6977,23.3219","43.6977,24.3219"]

    let distanceMeters = userlocation.distanceFromLocation(CLLocation(latitude: 42.6977,longitude: 23.3219))
    let distanceKilometers = distanceMeters / 1000.00
    let roundedDistanceKilometers = String(Double(round(100 * distanceKilometers) / 100)) + " km"
   // var distanceMeter = NSString(format: "\(distanceKilometers)km")

Answer 1

假设JSON文件位于应用程序包中并且名为cities.json，则首先创建一个自定义结构City

struct City {
  let name : String
  let location : CLLocation
}

然后在你的控制器中声明一个数组cities

 var cities = [City]()

填充数组反序列化JSON并提取数据

guard let url = NSBundle.mainBundle().URLForResource("cities", withExtension: "json"), jsonData = NSData(contentsOfURL: url) else { return }

do {
  let jsonObject = try NSJSONSerialization.JSONObjectWithData(jsonData, options: []) as! [String:AnyObject]
  for (cityName, position) in jsonObject {
    let coordinates = position["Position"] as! [String:CLLocationDegrees]
    let longitude = coordinates["Longitude"]!
    let latitude = coordinates["Latitude"]!
    let location = CLLocation(latitude: latitude,longitude: longitude)
    let city = City(name: cityName, location: location)
     cities.append(city)
    // print(cities)
  }
} catch let error as NSError {
  print(error)
}

要查找最近的位置，您可以按距离对数组进行排序

let nearestCity = cities.sort({ userLocation.distanceFromLocation($0.location) < userLocation.distanceFromLocation($1.location) }).first

如何将经度纬度从JSON文件填充到数组中

1 个答案: