A database of sqflite in flutter for todos

database.dart

import 'dart:async';
import 'dart:io';

import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:sqflite/sqflite.dart';

import 'package:meta/meta.dart';

class ToDo {
  @required
  int id;
  @required
  String title;
  @required
  String description;
  @required
  int orderItems;
  @required
  bool complete;
  @required
  String datetime;
  @required
  int priorty;

  ToDo(
      {this.id,
      this.title,
      this.description,
      this.orderItems,
      this.complete,
      this.datetime,
      this.priorty,
      this.subtasks});

  ToDo.fromDb(Map<String, dynamic> map)
      : id = map['id'],
        title = map['title'],
        description = map['description'],
        orderItems = map['order_items'],
        complete = map['complete'] == 1,
        datetime = map['datetime'],
        priorty = map['priorty'],
        subtasks = map['subtasks'];

  Map<String, dynamic> toMapForDb() {
    var map = Map<String, dynamic>();
    map['id'] = id;
    map['title'] = title;
    map['description'] = description;
    map['order_items'] = orderItems;
    map['complete'] = complete ? 1 : 0;
    map['datetime'] = datetime;
    map['priorty'] = priorty;
    map['subtasks'] = subtasks;
    return map;
  }
}

class ToDoDatabase {
  static final ToDoDatabase _instance = ToDoDatabase._();
  static Database _database;

  ToDoDatabase._();

  factory ToDoDatabase() {
    return _instance;
  }

  Future<Database> get db async {
    if (_database != null) {
      return _database;
    }

    _database = await initialize();

    return _database;
  }

  Future<Database> initialize() async {
    Directory directory = await getApplicationDocumentsDirectory();
    String dbPath = join(directory.path, 'database.db');
    var database = openDatabase(dbPath,
        version: 1, onCreate: _onCreate, onUpgrade: _onUpgrade);

    return database;
  }

  void _onCreate(Database db, int version) {
    db.execute('''
      CREATE TABLE todo(
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        title TEXT,
        description TEXT,
        order_items INTEGER,
        complete INTEGER,
        datetime TEXT,
        priorty INTEGER,
        subtasks TEXT)
    ''');
    print("Database was created!");
  }

  void _onUpgrade(Database db, int oldVersion, int newVersion) {
    // Run migration according database versions
  }

  Future<int> addToDo(ToDo todo) async {
    var client = await db;
    return client.insert('todo', todo.toMapForDb(),
        conflictAlgorithm: ConflictAlgorithm.replace);
  }

  Future<ToDo> fetchToDo(int id) async {
    var client = await db;
    final Future<List<Map<String, dynamic>>> futureMaps =
        client.query('todo', where: 'id = ?', whereArgs: [id]);
    var maps = await futureMaps;

    if (maps.length != 0) {
      return ToDo.fromDb(maps.first);
    }

    return null;
  }

  Future<List<ToDo>> fetchAll() async {
    var client = await db;
    var res = await client.query('todo');

    if (res.isNotEmpty) {
      List<ToDo> todo = res.map((todoMap) => ToDo.fromDb(todoMap)).toList();
      return todo;
    }
    return [];
  }

  Future<int> updateToDo(ToDo newToDo) async {
    var client = await db;
    return client.update('todo', newToDo.toMapForDb(),
        where: 'id = ?',
        whereArgs: [newToDo.id],
        conflictAlgorithm: ConflictAlgorithm.replace);
  }

  Future<void> removeToDo(int id) async {
    var client = await db;
    return client.delete('todo', where: 'id = ?', whereArgs: [id]);
  }

  Future<void> removeAll() async {
    var client = await db;
    return client.delete('todo');
  }

  Future dispose() async {
    var client = await db;
    client.close();
  }
}