Is there any alternative of converting the JSON response into a custom Dart object?-CodePudding

I am new to flutter and dart and making an application with nodejs backend with MongoDB as my database. When requesting data from flutter using HTTP package I noticed I have to convert the JSON to a custom Dart object.

I referred to the official document

Everything is working fine, but I find this conversion of data a very long process and unnecessary line of code if I have many different pages with a different types of data coming from the backend.

Is there any quick or better way to accomplish this? Thank you

CodePudding user response：

Dart is an Object Oriented Programming language.

That's why the official documentation is talking about converting your Json into a Dart Object :)
You could achieve the same things by having your Jsons as Maps<String, dynamic> instead of converting it to Dart Objects, but at the cost of an unnecessary complex code.

If you have a lot of models to use, you can use a library generating the parsing methods for you like json_serializable thank to some annotation processing, or even freezed which is generating even more useful methods.

Basic example of json_serializable :

import 'package:json_annotation/json_annotation.dart';

part 'user_agenda.g.dart';

@JsonSerializable()
class UserAgenda {
  String? uid;
  String? name;
  String? imgUrl;
  int? nextDate;

  UserAgenda() {}

  factory UserAgenda.fromJson(Map<String, dynamic> json) => _$UserAgendaFromJson(json);

  Map<String, dynamic> toJson() => _$UserAgendaToJson(this);

}

Personal opinion : in your case, go for json_serializable. Freezed may be overkill, and playing with the Maps will shortly become a real pain to maintain.

CodePudding user response：

For Converting JSON Response to Dart object you should use https://app.quicktype.io

Select Language as Dart. Please note that generated code will not a null safe code. so you have to take care of it.

CodePudding user response：

You don't need to convert the response to the Dart objects you made before. Just use

  Map<String, dynamic> answer = jsonDecode(response.body);

Then you can access any value by it's key like this:

 var x = answer['key1'][0]['key2'];

But You need to know each time the structure of JSON.