使用Alamofire和Swift返回嵌套JSON数组中的值

Question

swift，JSON和几乎所有编码都是超级新手，因此，如果这个问题对网站上的其他人多余，或者我在这里遗漏了一些简单的内容，我就向您道歉。

我正在寻找在下面的JSON代码的“元素”数组中返回与“距离”关联的“文本”（“ 1.7英里”）的值：

{
   "destination_addresses" : [ "30 Rockefeller Plaza, New York, NY 10112, USA" ],
   "origin_addresses" : [ "352 7th Ave, New York, NY 10001, USA" ],
   "rows" : [
      {
         "elements" : [
            {
               "distance" : {
                  "text" : "1.7 mi",
                  "value" : 2729
               },
               "duration" : {
                  "text" : "15 mins",
                  "value" : 887
               },
               "status" : "OK"
            }
         ]
      }
   ],
   "status" : "OK"
}

我使用Alamofire和Google DistanceMatrix检索了JSON数据（请参见下面的代码），但是在解析数据以隔离所需内容时遇到了麻烦。我知道下面的代码与我所需的代码并不接近，但是不确定如何进行。

func distanceMatrix(startLocation: String, endLocation: String) {
        let myOrigin = startLocationTFText
        let myDestination = destinationLocationTFText

        let url = "https://maps.googleapis.com/maps/api/distancematrix/json?units=imperial&origins=\(myOrigin)&destinations=\(myDestination)&key=API_Key

        let encodedUrl = url.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)

        AF.request(encodedUrl!).responseJSON { response in
            print(response.request as Any)
            print(response.response as Any)
            print(response.data as Any)
            print(response.result as Any)

            let json = JSON(response.data as Any)

非常感谢您的帮助。谢谢。

Answer 1

您可以使用Decodable获得所需的结果。

struct RootResponse: Decodable {

   let destinationAddresses, originAddresses: [String]
   let rows: [Rows]
   let status: String
}

struct Rows: Decodable {

  let elements: [Elements]
}

struct Elements: Decodable {

  let distance, duration: Details
  let status: String
}

struct Details: Decodable {
   let text, value: String
}

这将是您的模型文件，添加完成后，您可以返回到函数并将其用作：

func distanceMatrix(startLocation: String, endLocation: String) {
    let myOrigin = startLocationTFText
    let myDestination = destinationLocationTFText

    let url = "https://maps.googleapis.com/maps/api/distancematrix/json?units=imperial&origins=\(myOrigin)&destinations=\(myDestination)&key=API_Key"

    let encodedUrl = url.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)

    AF.request(encodedUrl!).responseJSON { response in
        print(response.request as Any)
        print(response.response as Any)
        print(response.data as Any)
        print(response.result as Any)

        let decoder = JSONDecoder()
        decoder.keyDecodingStrategy = .convertFromSnakeCase

        guard let json = try? decoder.decode(RootResponse.self, from: response.data) else { print("Unable to parse JSON"); return }

        print(json)
        print(json.rows.first?.elements.first?.distance.value) // This is how you can get the value, but it will be better to safely unwrap them and I have also used first? to get the first object but this is an array and you can always use a for loop for further purpose
}