如何使结构与这个json?

Question

如何使这个JSON结构模型?我在youtube上看了很多教程，但我仍然很困惑，在结构体上使用enum的意义是什么?

{
"err_code": 0,
"data": {
"message": "Success",
"result": {
"check_in": [
{
"created_at": "2022-06-20 10:00:37",
"late": "True",
"location": "Jl. H. Asmawi No.63, Beji, Kecamatan Beji, Kota Depok, Jawa Barat 16421, Indonesia",
"place": "GRIT OFFICE",
"folder": "./pegawai/grit/2022/06/20/masuk/10/00/",
"filename": "0000_rakha_fatih_athallah_picture.jpg",
"tujuan": "",
"link": "http://103.140.90.10:8081/face-recognition/client/python/pegawai/grit/2022/06/20/masuk/10/00/0000_rakha_fatih_athallah_picture.jpg"
},
{
"created_at": "2022-06-16 11:23:12",
"late": "True",
"location": "Jl. H. Asmawi No.63, Beji, Kecamatan Beji, Kota Depok, Jawa Barat 16421, Indonesia",
"place": "GRIT OFFICE",
"folder": "./pegawai/grit/2022/06/16/masuk/11/23/",
"filename": "0000_rakha_fatih_athallah_picture.jpg",
"tujuan": "",
"link": "http://103.140.90.10:8081/face-recognition/client/python/pegawai/grit/2022/06/16/masuk/11/23/0000_rakha_fatih_athallah_picture.jpg"
}
],
"check_out": []
}
}
}

这是我的结构模型。这很重要，因为我想使用jsondecoder与这个结构体。我想使用jsondecoder以后。

import Foundation
struct jsonData : Codable{
var err_code : Int
var data : Data

enum CodingKeys: String, CodingKey {
case err_code = "err_code"
case data = "data"
}
}
struct Data: Codable{
var message : String
var result  : Result
}
struct Result : Codable {
var check_in  : [Checkin] = []
}
struct Checkin : Codable{
var created_at : String
var late : String
var location : String
var place : String
var folder : String
var tujuan : String
var link : String

enum CodingKeys: String, CodingKey {
case created_at = "created_at"
case late = "late"
case location = "location"
case place = "place"
case folder = "folder"
case tujuan = "tujuan"
case link = "link"
}
}

Answer 1

我认为你所拥有的结构非常接近所需要的，只是轻微的调整，如:

struct Response: Codable{
var err_code: Int
var data: DataObj
}
struct DataObj: Codable{
var message: String
var result: Result
}
struct Result: Codable {
var check_in: [Checkin]
}
struct Checkin: Codable, Hashable {
var created_at: String
var late: String
var location: String
var place: String
var folder: String
var tujuan: String
var link: String
}

像这样使用:

struct ContentView: View {
@State var apiResponse: Response?

var body: some View {
VStack {
if let response = apiResponse {
Text("message: (response.data.message) ")
Text("check_in.count: (response.data.result.check_in.count) ")
List {
ForEach(response.data.result.check_in, id: .self) { chk in
Text("created_at: (chk.created_at) ")
}
}
}
}
.onAppear {
let jsonStr = """
{
"err_code": 0,
"data": {
"message": "Success",
"result": {
"check_in": [
{
"created_at": "2022-06-20 10:00:37",
"late": "True",
"location": "Jl. H. Asmawi No.63, Beji, Kecamatan Beji, Kota Depok, Jawa Barat 16421, Indonesia",
"place": "GRIT OFFICE",
"folder": "./pegawai/grit/2022/06/20/masuk/10/00/",
"filename": "0000_rakha_fatih_athallah_picture.jpg",
"tujuan": "",
"link": "http://103.140.90.10:8081/face-recognition/client/python/pegawai/grit/2022/06/20/masuk/10/00/0000_rakha_fatih_athallah_picture.jpg"
},
{
"created_at": "2022-06-16 11:23:12",
"late": "True",
"location": "Jl. H. Asmawi No.63, Beji, Kecamatan Beji, Kota Depok, Jawa Barat 16421, Indonesia",
"place": "GRIT OFFICE",
"folder": "./pegawai/grit/2022/06/16/masuk/11/23/",
"filename": "0000_rakha_fatih_athallah_picture.jpg",
"tujuan": "",
"link": "http://103.140.90.10:8081/face-recognition/client/python/pegawai/grit/2022/06/16/masuk/11/23/0000_rakha_fatih_athallah_picture.jpg"
}
],
"check_out": []
}
}
}
"""
// simulated response data
let data = jsonStr.data(using: .utf8)!
do {
self.apiResponse = try JSONDecoder().decode(Response.self, from: data)
print("n---> apiResponse (apiResponse)")
}
catch {
print(" error (error)")
}
}
}
}

Answer 2

我们使用CodingKeys是为了在JSON中使用自定义名称。

例如，您有created_at，但您不想要下划线，您要做的是将变量命名为createdAt，并在enum中添加case createdAt = "created_at"

至于解码部分，实际上很简单:

do {
//let data = the json data you got.
let decoder = JSONDecoder()
let model = try decoder.decode(jsonData.self, from: data)
}catch {
print(String(describing: error))
}

请注意，我们在命名structs, classes, actors & enums时不使用小写字母。

编辑:感谢Marek R指出，有时JSON中的名称可以匹配特定于所使用语言的关键字(即:Swift)，因此有必要实现CodingKeys。