如何在Swift 4中解析具有字典和数组的JSON？

Question

I need some help on parsing a JSON in Swift 4, I already know how to do it with a simple JSON like this one:

{"numNotif":1,"numTqClose":7,"reply":3}

But now I have to parse another JSON that is so huge, it has this structure: https://textuploader.com/dnx8f

And this is how I parse a simple JSON but it is not working in this case

import UIKit
struct closeDtoList: Decodable {
  let CategoryStr:String
}
class test: UIViewCOntroller {
  super.viewDidLoad() {
    let urlJSON = "http://www.example.net/site/gitAll"
    guard let url = URL(string: urlJSON) else {return}
    URLSession.shared.dataTask(with: url) { (data, response, error) in
      guard let data = data else {return}
      guard error == nil else {return}
      do {
        let closeDto = try JSONDecoder().decode(closeDtoList.self, from: data)
        print(closeDto.CategoryStr)
      } catch let error {
        print(error)
  }.resume()
}

Well, so I would like to use the same code or a similar one in order to parse a JSON that has dictionaries "{}" and arrays "[]" before the values, so in fact I want to get the value of issueId, CategoryStr and so on, but I do not have any idea about how to do it.

Also, I would need to save these values in an array (each value in each field), will it be possible?

Thank you in advance!

Answer 1

You can create ToDoList struct which contains closeDtoList, openDtoList structs as params. The structure would look like below. The IssueId type is not clear from the json, change it to match the requirement.

import Foundation

struct ToDoList: Decodable {
    let closeDtoList, openDtoList: [DtoList]
}

struct DtoList: Decodable {
    let issueID: IssueID
    let issueStr, categoryStr: String
    let hasImg: Bool
    let tasksID: IssueID
    let userAssign, userStart: Int

    enum CodingKeys: String, CodingKey {
        case issueID = "issueId"
        case issueStr
        case categoryStr = "CategoryStr"
        case hasImg
        case tasksID = "tasksId"
        case userAssign, userStart
    }
}

struct IssueID: Decodable {

    let id: Int?

    enum CondingKeys: String, CodingKey {
        case id = "id" //replace this with correct id value
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CondingKeys.self)
        if let issueId = try? container.decodeIfPresent(Int.self, forKey: .id) {
            self.id = issueId
        } else {
            self.id = nil
        }
    }
}

Answer 2

All you need to do is to parse the JSON according to your structure. For example:

if let responseObj = try? JSONSerialization.jsonObject(with: data) {
   if let responseData = responseObj as? [String: Any] { // Parse dictionary
      if let closeDtoList = responseData["closeDtoList"] as? [[String: Any]] {// Parse an array containing dictionaries
         if closeDtoList.count > 0 {
            // You should use a loop here but I'm just doing this way to show an example
            if let issueStr = closeDtoList[0]["issueStr"] as? String { // Parse a string from dictionary

            }
         }
      }
   }
}

data is what you get from your URLSession call. Basically you cast the JSON object to whatever structure you know that it has. In above example I parse responseObj as a Dictionary then I retrieve closeDtoList key's value from this dictionary as Array of Dictionaries and from the first element of that array (which is a dictionary) I get issueStr key's value which is a String .