使用 Alamofire 和 Swift 返回嵌套 JSON 数组中的值

Posted 2023-02-24

【中文标题】使用 Alamofire 和 Swift 返回嵌套 JSON 数组中的值

【英文标题】：Return a value in a nested JSON array, using Alamofire and Swift

【发布时间】：2020-03-17 02:56:22

【问题描述】：

对于 swift、JSON 和几乎所有编码都是超级新手，所以如果这个问题对网站上的其他人来说是多余的，或者我在这里遗漏了一些简单的东西，我提前道歉。

我希望在下面的 JSON 代码中的“元素”数组中返回与“距离”相关的“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（请参阅下面的代码），但无法解析数据以隔离我需要的内容。我知道下面的代码不符合我的需要，但不确定如何继续。

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)

非常感谢任何帮助。谢谢。

【问题讨论】：

您必须使用 Amlofire 探索 Codable 协议。上面有一个很棒的博客：medium.com/@AladinWay/…

【参考方案1】：

您可以使用Decodable 来获得想要的结果。

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，一旦您添加了它，您就可以返回到您的函数并将其用作：

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

【讨论】：

@LittleRocketMan 欢迎！