Not able to modify Codable Class Properties?

问题

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
}
}

encode to User Object

 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
 }

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

when i tried

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

Again same result

also tried with mutating func

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

Not able to modify existing values.

回答1:

Change let to var when declaring userInfo;

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

来源：https://stackoverflow.com/questions/48375826/not-able-to-modify-codable-class-properties

标签

swift

properties

codable