Flutter – Convert JSON to Model Class in Dart

Many times you are receiving API data but it is difficult to create a model class manually for some data that are too big. So we can make a model with just 2 steps. Let’s take sample data for which we want to create a model class.

{
  "userId": 1,
  "id": 1,
  "title": "delectus aut autem",
  "completed": false
}

Step-by-Step Implementation

Step 1: Just Copy the Data you want to create a model class for.

Step 2: Go to this website.

Step 3: Paste it and give a name to the model class.

Step 4: Copy the Model class and use it in your flutter or dart projects.

Model Class Sample 

1. With private field 

Dart

class TodoModel {
  int? _userId;
  int? _id;
  String? _title;
  bool? _completed;

  TodoModel({int? userId, int? id, String? title, bool? completed}) {
    if (userId != null) {
      this._userId = userId;
    }
    if (id != null) {
      this._id = id;
    }
    if (title != null) {
      this._title = title;
    }
    if (completed != null) {
      this._completed = completed;
    }
  }

  int? get userId => _userId;
  set userId(int? userId) => _userId = userId;
  int? get id => _id;
  set id(int? id) => _id = id;
  String? get title => _title;
  set title(String? title) => _title = title;
  bool? get completed => _completed;
  set completed(bool? completed) => _completed = completed;

  TodoModel.fromJson(Map<String, dynamic> json) {
    _userId = json['userId'];
    _id = json['id'];
    _title = json['title'];
    _completed = json['completed'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['userId'] = this._userId;
    data['id'] = this._id;
    data['title'] = this._title;
    data['completed'] = this._completed;
    return data;
  }
}

2. Without a Private Field

Dart

class TodoModel {
  int? userId;
  int? id;
  String? title;
  bool? completed;

  TodoModel({this.userId, this.id, this.title, this.completed});

  TodoModel.fromJson(Map<String, dynamic> json) {
    userId = json['userId'];
    id = json['id'];
    title = json['title'];
    completed = json['completed'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['userId'] = this.userId;
    data['id'] = this.id;
    data['title'] = this.title;
    data['completed'] = this.completed;
    return data;
  }
}