I have a json file which looks like this:

[
  {
    "tn_newsid": 144377,
    "tn_midashi": "知床半島とオホーツク海の絶景が広がる",
    "tn_name": "北海道立オホーツク公園オートキャンプ場てんとらんど",
    "tn_ktel": "0152-45-27",
    "tn_url": "",
    "tn_kdo": 144.239526856306,
    "tn_ido": 43.9880220633556,
    "tn_im1name": "144377_1.jpg",
    "tn_im2name": "144377_2.jpg",
    "tn_im3name": "144377_3.jpg",
    "tn_im4name": "144377_4.jpg",
    "type": 0,
    "nico_recommended": 0
  },
  {
// etc ....

Untill now I was getting the data with this code snipped

seasonInfoService.seasonServerDataJson(jsoncompleted: { () in
let responseData: Data =  self.seasonInfoService.UpdateJsonString.data(using: String.Encoding.utf8)!
    do{
        let items = try JSONSerialization.jsonObject(with: responseData) as! Dictionary<String,Any>

But the json file starts with [ so I need to change Dictionary<String,Any> to NSArray

because Im getting this error code

Could not cast value of type '__NSArrayI' (0x7fff86cd0128) to 'NSDictionary' 

and my code now looks like

facilitiesService.facilitiesServerDataJson(urlToFetch: url_, jsoncompleted: { () in
let responseData: Data =  self.facilitiesService.UpdateJsonString.data(using: String.Encoding.utf8)!
    do{
        let items = try JSONSerialization.jsonObject(with: responseData) as! NSArray
        print(items)

But the print statement shows only [ , how can I change this to proper list of dictionaries please?

CodePudding user response：

First create a struct that conforms to Decodable. It's good/necessary to map the JSON data.

struct MyStruct: Decodable {
    let tn_newsid: Int
    let tn_midashi: String
    let tn_name: String
    let tn_ktel: String
    let tn_url: String
    let tn_kdo: Double
    let tn_ido: Double
    let tn_im1name: String
    let tn_im2name: String
    let tn_im3name: String
    let tn_im4name: String
    let type: Int
    let nico_recommended: Int

}

Then let's say your JSON response looks like this:

let responseData: String = """
        [
        {
          "tn_newsid": 1477,
          "tn_midashi": "知床半島とオホーツク海の絶景が広がる",
          "tn_name": "北海道立オホーツク公園オートキャンプ場てんとらんど",
          "tn_ktel": "0152-45-27",
          "tn_url": "",
          "tn_kdo": 144.239526856306,
          "tn_ido": 43.9880220633556,
          "tn_im1name": "144377_1.jpg",
          "tn_im2name": "144377_2.jpg",
          "tn_im3name": "144377_3.jpg",
          "tn_im4name": "144377_4.jpg",
          "type": 0,
          "nico_recommended": 2
        },
        {
          "tn_newsid": 144377,
          "tn_midashi": "知ホーツク海の絶景が広がる",
          "tn_name": "北海道立オホートキャンプ場てんとらんど",
          "tn_ktel": "0152-45-27",
          "tn_url": "",
          "tn_kdo": 144.239526856306,
          "tn_ido": 46.9880220633556,
          "tn_im1name": "144377_1.jpg",
          "tn_im2name": "144377_2.jpg",
          "tn_im3name": "144377_3.jpg",
          "tn_im4name": "144377_4.jpg",
          "type": 0,
          "nico_recommended": 0
        }
            ]
            """

Now parse the response like this:

let jsonData = responseData.data(using: .utf8)!
let decodedItems: [MyStruct] = try! JSONDecoder().decode([MyStruct].self, from: jsonData)
decodedItems.forEach({print(">>> \($0)")})

In practice, you'd better avoid force-unwrapping data and decoded items.

Output:

>>> MyStruct(tn_newsid: 1477, tn_midashi: "知床半島とオホーツク海の絶景が広がる", tn_name: "北海道立オホーツク公園オートキャンプ場てんとらんど", tn_ktel: "0152-45-27", tn_url: "", tn_kdo: 144.239526856306, tn_ido: 43.9880220633556, tn_im1name: "144377_1.jpg", tn_im2name: "144377_2.jpg", tn_im3name: "144377_3.jpg", tn_im4name: "144377_4.jpg", type: 0, nico_recommended: 2)
>>> MyStruct(tn_newsid: 144377, tn_midashi: "知ホーツク海の絶景が広がる", tn_name: "北海道立オホートキャンプ場てんとらんど", tn_ktel: "0152-45-27", tn_url: "", tn_kdo: 144.239526856306, tn_ido: 46.9880220633556, tn_im1name: "144377_1.jpg", tn_im2name: "144377_2.jpg", tn_im3name: "144377_3.jpg", tn_im4name: "144377_4.jpg", type: 0, nico_recommended: 0)