从 JSON 中获取多个字符串

Question

所以 JSON 变量 let json = JSON(nearbyChargingSites.jsonString!) 包含当前数据。：

{
  "timestamp" : 1626902257093,
  "superchargers" : [
    {
      "location" : {
        "lat" : 63.325319,
        "long" : 10.305137
      },
      "total_stalls" : 19,
      "distance_miles" : 10.064082000000001,
      "type" : "supercharger",
      "site_closed" : false,
      "available_stalls" : 15,
      "name" : "Leinstrand, Norway - Klett"
    },
    {
      "location" : {
        "lat" : 63.466445999999998,
        "long" : 10.91766
      },
      "total_stalls" : 16,
      "distance_miles" : 11.838984999999999,
      "type" : "supercharger",
      "site_closed" : false,
      "available_stalls" : 16,
      "name" : "Stjørdal, Norway"
    },
    {
      "location" : {
        "lat" : 63.734355000000001,
        "long" : 11.281487
      },
      "total_stalls" : 12,
      "distance_miles" : 31.206503999999999,
      "type" : "supercharger",
      "site_closed" : false,
      "available_stalls" : 11,
      "name" : "Levanger, Norway"
    },
    {
      "location" : {
        "lat" : 62.832030000000003,
        "long" : 10.009639999999999
      },
      "total_stalls" : 20,
      "distance_miles" : 44.117753,
      "type" : "supercharger",
      "site_closed" : false,
      "available_stalls" : 17,
      "name" : "Berkåk, Norway"
    }
  ],
  "congestion_sync_time_utc_secs" : 1626902199,
  "destination_charging" : [
    {
      "distance_miles" : 23.366278999999999,
      "name" : "Bårdshaug Herregård",
      "location" : {
        "lat" : 63.299208,
        "long" : 9.8448650000000004
      },
      "type" : "destination"
    },
    {
      "distance_miles" : 38.390034,
      "name" : "Fosen Fjordhotel",
      "location" : {
        "lat" : 63.959356999999997,
        "long" : 10.223908
      },
      "type" : "destination"
    },
    {
      "distance_miles" : 46.220022999999998,
      "name" : "Falksenteret",
      "location" : {
        "lat" : 63.293301999999997,
        "long" : 9.0834460000000004
      },
      "type" : "destination"
    },
    {
      "distance_miles" : 54.981445000000001,
      "name" : "Væktarstua",
      "location" : {
        "lat" : 62.908683000000003,
        "long" : 11.893306000000001
      },
      "type" : "destination"
    }
  ]
}

我使用SwiftyJSON 并尝试获取增压器的纬度、经度和名称，如下所示：

let jsonName = json["superchargers"]["name"]
let jsonLat = json["superchargers"]["location"]["lat"]
let jsonLong = json["superchargers"]["location"]["long"]
            

当尝试打印其中任何一个时，它们都返回nil。

任何想法我做错了什么，以及如何做到这一点？

我想这样做是因为我想将它们作为annotation 添加到MKMapView。

Answer 1

第一个错误是您使用的 JSON 初始化程序将创建单个 JSON 字符串对象，它不会将字符串解析为 JSON 数据：

代替：

let json = JSON(nearbyChargingSites.jsonString!)

你需要使用：

let json = JSON(data: dataFromJSONString)

其次，您需要遍历增压器数组以收集所有值

尝试类似：

    if let dataFromString = nearbyChargingSites.jsonString!.data(using: .utf8, allowLossyConversion: false) {
        let json = try! JSON(data: dataFromString,options: .allowFragments)

        for supercharger in json["superchargers"].arrayValue {
            let jsonName = supercharger["name"].stringValue
            let jsonLat = supercharger["location"]["lat"].doubleValue
            let jsonLong = supercharger["location"]["long"].doubleValue
        }
    }

请注意，上述代码不执行错误处理，如果 JSON 中缺少值，则会崩溃。