how can I pass a json string to object? - json

Question

my problem is the next, I have a this json
{
"nombre" : "userProfile.user.name!",
"apaterno" : 20,
"amaterno" : true,
"email" : 100,
"start_screen" : {
"info" : true,
"title" : false,
"image" : 20,
"success_btn" : "hola",
"close_btn" : true
}
}
i want to pass this json to my struct, my struct is :
struct person: Decodable
{
var email : Int
var nombre : String
var apaterno : Int
var amaterno: Bool
struct start_screen {
var title: Bool
var info: Bool
var image: Int
var success_btn: String
var close_btn: Bool
}
}
with the next lines I achieved put the json in my struct, but start_screen struct can't get the data.
let jsonData = json.data(using: .utf8)!
let decoder = JSONDecoder()
let myStruct = try! decoder.decode(person.self, from: jsonData)
when I access myStruct.email I get 100, its ok, but I can't load the start_screen data, how should I do it?

Answer 1

First you would need to add a variable to person for start_screen.
var start_screen: start_screen
Then you would need to make start_screen Decodable
struct start_screen: Decodable
That should be the minimum amount of changes to get it working.
Additionally, you might want to make your types capitalized. start_screen: start_screen is really confusing looking. You can also make your variable and type names camelCase and have the JSONDecoder convert to/from snake_case for you. It's also the naming convention in swift. It'd look like this
struct Person: Decodable {
var email: Int
var nombre: String
var apaterno: Int
var amaterno: Bool
var startScreen: StartScreen
struct StartScreen: Decodable {
var title: Bool
var info: Bool
var image: Int
var successBtn: String
var closeBtn: Bool
}
}
let jsonData = json.data(using: .utf8)!
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let person = try! decoder.decode(Person.self, from: jsonData)
print(person)

Answer 2

This should be your Person struct :
struct Person: Decodable {
var email : Int?
var nombre : String?
var apaterno : Int?
var amaterno: Bool
var start_screen: Start_screen?
enum CodingKeys: String, CodingKey {
case email = "email"
case nombre = "nombre"
case apaterno = "apaterno"
case amaterno = "amaterno"
case start_screen = "amaterno"
}
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
email = try values.decodeIfPresent(Int.self, forKey: .email)
nombre = try values.decodeIfPresent(String.self, forKey: .nombre)
apaterno = try values.decodeIfPresent(Int.self, forKey: .apaterno)
amaterno = try values.decodeIfPresent(Bool.self, forKey: .apaterno) ?? false
start_screen = try values.decodeIfPresent(Start_screen.self, forKey: .start_screen)
}
}
This should be your Start_screen struct :
struct Start_screen: Decodable {
var title: Bool
var info: Bool
var image: Int?
var success_btn: String?
var close_btn: Bool
enum CodingKeys: String, CodingKey {
case title = "title"
case info = "info"
case image = "image"
case success_btn = "success_btn"
case close_btn = "close_btn"
}
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
title = try values.decodeIfPresent(Bool.self, forKey: .title) ?? false
info = try values.decodeIfPresent(Bool.self, forKey: .info) ?? false
image = try values.decodeIfPresent(Int.self, forKey: .image)
success_btn = try values.decodeIfPresent(String.self, forKey: .success_btn)
close_btn = try values.decodeIfPresent(Bool.self, forKey: .close_btn) ?? false
}
}
Accessing start_screen from Person :
if let jsonData = json.data(using: .utf8) {
let user = try! JSONDecoder().decode(Person.self, from: jsonData)
if let title = user.start_screen.title {
print(title)
}
}