はじめに
- 作成途中のプログラムになりますが、Flutterでsqlliteを利用してタスクの登録と削除を行えるアプリを開発する。
※変更処理は途中の状態です。
インストールのパッケージ
- sqfliteとpath_providerをインストールする
dependencies:
flutter:
sdk: flutter
cupertino_icons: ^1.0.2
sqflite: ^2.0.2
path_provider: ^2.0.8
コード
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'next_page.dart';
void main() {
WidgetsFlutterBinding.ensureInitialized();
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key}) : super(key: key);
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
final textController = TextEditingController();
int? selectedId;
int tabIndex = 1;
@override
Widget build(BuildContext context) {
return MaterialApp(
home:Scaffold(
appBar: AppBar(
title: Text("タスク管理")
),
body: Center(
child: FutureBuilder<List<Task>>(
future: DatabaseHelper.instance.getTasks(),
builder: (BuildContext context,
AsyncSnapshot<List<Task>> snapshot) {
if (!snapshot.hasData) {
return Center(child: Text('Loading...'));
}
return snapshot.data!.isEmpty
? Center(child: Text('No Tasks.'))
: ListView(
children: snapshot.data!.map((task) {
return Center(
child: Card(
color: selectedId == task.id
? Colors.white70
: Colors.white,
child: ListTile(
title: Text(task.name),
onTap: () {
if (selectedId == null) {
textController.text = task.name;
selectedId = task.id;
} else {
textController.text = '';
selectedId = null;
}
},
onLongPress: () {
setState(() {
DatabaseHelper.instance.remove(task.id!);
});
},
),
)
);
}).toList(),
);
}),
),
floatingActionButton: FloatingActionButton(
child: Icon(Icons.save),
onPressed: ()async {
selectedId != null
? await DatabaseHelper.instance.update(
Task(id: selectedId, name: textController.text),
)
: await DatabaseHelper.instance.add(
Task(name: textController.text),
);
setState(() {
textController.clear();
selectedId = null;
});
},
),
bottomNavigationBar: BottomNavigationBar(
currentIndex: tabIndex,
items: [
BottomNavigationBarItem(
label: 'Home',
icon: Icon(Icons.home),
),
BottomNavigationBarItem(
label: 'AC Unit',
icon: Icon(Icons.ac_unit),
),
],
onTap: (int index) {
setState((){
tabIndex = index;
});
showDialog(
context: context,
builder: (_) {
return AlertDialog(
title: Text("タイトル"),
content: TextField(
controller: textController,
),
actions: <Widget>[
// ボタン領域
ElevatedButton(
child: Text("Cancel"),
onPressed: () => Navigator.pop(context),
),
ElevatedButton(
child: Text("OK"),
onPressed: () async {
selectedId != null
? await DatabaseHelper.instance.update(
Task(id: selectedId, name: textController.text),
)
: await DatabaseHelper.instance.add(
Task(name: textController.text),
);
setState(() {
textController.clear();
selectedId = null;
});
//Navigator.push(context, MaterialPageRoute(builder: (context) => NextPage()))
},
),
],
);
},
);
//Navigator.push(context, MaterialPageRoute(builder: (context) => NextPage()));
},
),
)
);
}
}
class Task {
final int? id;
final String name;
Task({this.id, required this.name});
factory Task.fromMap(Map<String, dynamic>json) => new Task(
id: json['id'],
name: json['name']
);
Map<String, dynamic> toMap() {
return {
'id': id,
'name': name
};
}
}
class DatabaseHelper {
DatabaseHelper._privateConstructor();
static final DatabaseHelper instance = DatabaseHelper._privateConstructor();
static Database? _database;
Future<Database> get database async => _database ??= await _initDatabase();
Future<Database> _initDatabase() async {
Directory documentsDirectory = await getApplicationDocumentsDirectory();
String path = join(documentsDirectory.path, 'tasks.db');
return await openDatabase(
path,
version: 1,
onCreate: _onCreate,
);
}
Future _onCreate(Database db, int version) async {
await db.execute('''
CREATE TABLE tasks(
id INTEGER PRIMARY KEY,
name TEXT
)
''');
}
Future<List<Task>> getTasks() async {
Database db = await instance.database;
var tasks = await db.query('tasks', orderBy: 'name');
List<Task> taskList = tasks.isNotEmpty
? tasks.map((c) => Task.fromMap(c)).toList()
: [];
return taskList;
}
Future<int> update(Task task) async {
Database db = await instance.database;
return await db.update('tasks', task.toMap(),
where: "id = ?", whereArgs: [task.id]);
}
Future<int> add(Task task) async {
Database db = await instance.database;
return await db.insert('tasks', task.toMap());
}
Future<int> remove(int id) async {
Database db = await instance.database;
return await db.delete('tasks', where: 'id = ?', whereArgs: [id]);
}
}
作成した画面
