无法修改可编码类属性？ [英] Not able to modify Codable Class Properties?

问题描述

Swift开发的新功能。我的USER JSON有一个类结构。我能够将JSON值编码为User对象，但是当我想要修改这些属性时，更改不会反映在类结构中。

New in Swift development. I have a class structure for my USER JSON. I am able to encode JSON value to User object but when I want to modify these properties changes not reflected in a class structure. Can you please help me.

import Foundation
struct UserInfo : Codable {
let userId : String?
var firstName : String?
var lastName : String?
let email : String?
let phone : String?

enum CodingKeys: String, CodingKey {

    case userId = "userId"
    case firstName = "firstName"
    case lastName = "lastName"
    case email = "email"
    case phone = "phone"

}

init(from decoder: Decoder) throws {
    let values = try decoder.container(keyedBy: CodingKeys.self)
    userId = try values.decodeIfPresent(String.self, forKey: .userId)
    firstName = try values.decodeIfPresent(String.self, forKey: .firstName)
    lastName = try values.decodeIfPresent(String.self, forKey: .lastName)
    email = try values.decodeIfPresent(String.self, forKey: .email)
    phone = try values.decodeIfPresent(String.self, forKey: .phone)

}
//trying with mutating function but not able to modify
mutating func update(firstName fName: String) {
    self.firstName = fName
}

mutating func update(email newMail: String) {
    self.email = newMail
}
}

编码为用户对象

 let jsonDecoder = JSONDecoder()
 let responseModel = try jsonDecoder.decode(LoginResponseBody.self, from: data)
 if let userInfo = responseModel.responseBody {
  // get userInfo object
  print(userInfo.firstName) // output: Vishal
 }

我的问题是，如何修改上面的对象值，而且还是var类型？

My question is how can i modify above object values and also it's a var type

我尝试过

userInfo.firstName = "something other"
print(userInfo.firstName)// output: Vishal

再次获得相同的结果

也尝试了对func进行突变

also tried with mutating func

userInfo.update(firstName: "something other")
print(userInfo.firstName) // output: Vishal

无法修改现有值。

推荐答案

在以下情况下将其更改为var声明userInfo;

Change let to var when declaring userInfo;

if var userInfo = responseModel.responseBody {
  // get userInfo object
  userInfo.firstName = "something other"
  print(userInfo.firstName)
 }

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