How to do a toJson encode method on Dart/Flutter? - flutter

Question

I used the fromJson method to recover a Struct with a List from Json decode http request and receiver it on my class, but now i want to do a reverse, i want to pass the data on my class to my toJson method and send him to a Json encode http POST. Please, i new on Dart/Flutter, someone know how to do this?
import 'dart:convert';
List<Itens> userFromJson(String str) =>
List<Itens>.from(jsonDecode(str).map((x) => Itens.fromJson(x)));
class Coletas {
final int codigo;
final String dataIni;
late String? dataFin;
late String? status;
final List<Itens> itemList;
Coletas(
{
required this.dataIni,
this.dataFin,
this.status,
required this.codigo,
required this.itemList
}
);
factory Coletas.fromJson(Map<String, dynamic> json) {
return Coletas(
dataIni: json['dtData'],
codigo: json['iCodigo'],
itemList: List<Itens>.from(json['stItens'].map((x) => Itens.fromJson(x))),
);
}
Map<String, dynamic> toMap() {
return {
'codigo': codigo,
'dataIni': dataIni,
'dataFin': dataFin,
'status': status
};
}
}
class Itens {
final int? id;
final int codigo;
late int quantidade;
late String? status;
final String codigoEAN;
Itens({
this.id,
this.status,
required this.codigo,
required this.codigoEAN,
required this.quantidade,
});
Map<String, dynamic> toJson(){
return {
'icodigo' : codigo,
'sCodigoBarras': codigoEAN,
'iQtd': quantidade
};
}
factory Itens.fromJson(Map<String, dynamic> json) {
return Itens(
codigo: json['iCodigo'],
codigoEAN: json['sCodigoBarras'],
quantidade: json['iQtd'],
);
}
Map<String, dynamic> toMap() {
return {
'id': id,
'status': status,
'codigo': codigo,
'codigoEAN': codigoEAN,
'quantidade': quantidade,
};
}
}
I tried to pass ever item on List separeted so, but not happen i expected.
Map<String, dynamic> toJSon(Coletas value) =>
{
'dtData' : dataIni,
'iCodigo': codigo,
'stItens': [],
};

Answer 1

For a better structure - format and use you can look at the flutter serialization documentation : https://docs.flutter.dev/development/data-and-backend/json.
It explains how to create your model and how to generate them to create fromJson and toJson Model based on the defined data. (https://docs.flutter.dev/development/data-and-backend/json#creating-model-classes-the-json_serializable-way)
It will helps you with your parsing - sending - receiving data.

Answer 2

I think you should assign Coletas as
Map<String, dynamic> toJSon(Coletas value) =>
{
'dtData' : value.dataIni,
'iCodigo': value.codigo,
'stItens': value.itemList,
};