🏖️

Isar Databaseを使ってみた

2023/06/23に公開

Flutter

Isar

tech

Isarとは?

Isarとは、Hiveと呼ばれているローカルDBの後継として開発されたそうです。今回もただのメモ機能ですが、作るのが意外と難しかったので、記事にしようと思いました。
公式ドキュメント通りにやっても上手くいきません!

動画も作りました

https://youtu.be/2Knlrn0gOLM

必要なパッケージを追加する

このパッケージは、ここに追加したパッケージを配置しろとルールがあるみたいで、yamlファイルを見て、必要なパッケージを追加してください。この通りにやらないとハマりました!

pubspec.yaml

name: isar_app
description: A new Flutter project.
# The following line prevents the package from being accidentally published to
# pub.dev using `flutter pub publish`. This is preferred for private packages.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number is used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
# In Windows, build-name is used as the major, minor, and patch parts
# of the product and file versions while build-number is used as the build suffix.
version: 1.0.0+1

environment:
  sdk: '>=3.0.5 <4.0.0'

# Dependencies specify other packages that your package needs in order to work.
# To automatically upgrade your package dependencies to the latest versions
# consider running `flutter pub upgrade --major-versions`. Alternatively,
# dependencies can be manually updated by changing the version numbers below to
# the latest version available on pub.dev. To see which dependencies have newer
# versions available, run `flutter pub outdated`.
dependencies:
  flutter:
    sdk: flutter


  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^1.0.2
  isar: ^3.1.0+1
  isar_flutter_libs: ^3.1.0+1
  path_provider: ^2.0.15

dev_dependencies:
  flutter_test:
    sdk: flutter

  # The "flutter_lints" package below contains a set of recommended lints to
  # encourage good coding practices. The lint set provided by the package is
  # activated in the `analysis_options.yaml` file located at the root of your
  # package. See that file for information about deactivating specific lint
  # rules and activating additional ones.
  flutter_lints: ^2.0.0
  isar_generator: ^3.1.0+1 # isar_generatorはこの位置に配置する
  build_runner: ^2.4.4 # build_runnerはこの位置に配置する

# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec

# The following section is specific to Flutter packages.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  # assets:
  #   - images/a_dot_burr.jpeg
  #   - images/a_dot_ham.jpeg

  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.dev/assets-and-images/#resolution-aware

  # For details regarding adding assets from package dependencies, see
  # https://flutter.dev/assets-and-images/#from-packages

  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.dev/custom-fonts/#from-packages

モデルクラスを作る

今回は、公式のコードを修正して使わせていただきました。

lib/model/person.dart

import 'package:isar/isar.dart';// 1. isarパッケージをインポート
part 'person.g.dart';// ファイル名.g.dartと書く

@collection
class Person {
  Id id = Isar.autoIncrement; // id = nullでも自動インクリメントされます。

  String? name;
}

ファイルを自動生成するコマンドを実行する

flutter pub run build_runner build

こちらが自動生成されたファイル

PersonSchemaという定数をmain.dartで使用します。このコードを使って、Isarにアプリを接続します。

lib/model/person.g.dart

// GENERATED CODE - DO NOT MODIFY BY HAND

part of 'person.dart';

// **************************************************************************
// IsarCollectionGenerator
// **************************************************************************

// coverage:ignore-file
// ignore_for_file: duplicate_ignore, non_constant_identifier_names, constant_identifier_names, invalid_use_of_protected_member, unnecessary_cast, prefer_const_constructors, lines_longer_than_80_chars, require_trailing_commas, inference_failure_on_function_invocation, unnecessary_parenthesis, unnecessary_raw_strings, unnecessary_null_checks, join_return_with_assignment, prefer_final_locals, avoid_js_rounded_ints, avoid_positional_boolean_parameters, always_specify_types

extension GetPersonCollection on Isar {
  IsarCollection<Person> get persons => this.collection();
}

const PersonSchema = CollectionSchema(
  name: r'Person',
  id: 7854610480646705599,
  properties: {
    r'name': PropertySchema(
      id: 0,
      name: r'name',
      type: IsarType.string,
    )
  },
  estimateSize: _personEstimateSize,
  serialize: _personSerialize,
  deserialize: _personDeserialize,
  deserializeProp: _personDeserializeProp,
  idName: r'id',
  indexes: {},
  links: {},
  embeddedSchemas: {},
  getId: _personGetId,
  getLinks: _personGetLinks,
  attach: _personAttach,
  version: '3.1.0+1',
);

int _personEstimateSize(
  Person object,
  List<int> offsets,
  Map<Type, List<int>> allOffsets,
) {
  var bytesCount = offsets.last;
  {
    final value = object.name;
    if (value != null) {
      bytesCount += 3 + value.length * 3;
    }
  }
  return bytesCount;
}

void _personSerialize(
  Person object,
  IsarWriter writer,
  List<int> offsets,
  Map<Type, List<int>> allOffsets,
) {
  writer.writeString(offsets[0], object.name);
}

Person _personDeserialize(
  Id id,
  IsarReader reader,
  List<int> offsets,
  Map<Type, List<int>> allOffsets,
) {
  final object = Person();
  object.id = id;
  object.name = reader.readStringOrNull(offsets[0]);
  return object;
}

P _personDeserializeProp<P>(
  IsarReader reader,
  int propertyId,
  int offset,
  Map<Type, List<int>> allOffsets,
) {
  switch (propertyId) {
    case 0:
      return (reader.readStringOrNull(offset)) as P;
    default:
      throw IsarError('Unknown property with id $propertyId');
  }
}

Id _personGetId(Person object) {
  return object.id;
}

List<IsarLinkBase<dynamic>> _personGetLinks(Person object) {
  return [];
}

void _personAttach(IsarCollection<dynamic> col, Id id, Person object) {
  object.id = id;
}

extension PersonQueryWhereSort on QueryBuilder<Person, Person, QWhere> {
  QueryBuilder<Person, Person, QAfterWhere> anyId() {
    return QueryBuilder.apply(this, (query) {
      return query.addWhereClause(const IdWhereClause.any());
    });
  }
}

extension PersonQueryWhere on QueryBuilder<Person, Person, QWhereClause> {
  QueryBuilder<Person, Person, QAfterWhereClause> idEqualTo(Id id) {
    return QueryBuilder.apply(this, (query) {
      return query.addWhereClause(IdWhereClause.between(
        lower: id,
        upper: id,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterWhereClause> idNotEqualTo(Id id) {
    return QueryBuilder.apply(this, (query) {
      if (query.whereSort == Sort.asc) {
        return query
            .addWhereClause(
              IdWhereClause.lessThan(upper: id, includeUpper: false),
            )
            .addWhereClause(
              IdWhereClause.greaterThan(lower: id, includeLower: false),
            );
      } else {
        return query
            .addWhereClause(
              IdWhereClause.greaterThan(lower: id, includeLower: false),
            )
            .addWhereClause(
              IdWhereClause.lessThan(upper: id, includeUpper: false),
            );
      }
    });
  }

  QueryBuilder<Person, Person, QAfterWhereClause> idGreaterThan(Id id,
      {bool include = false}) {
    return QueryBuilder.apply(this, (query) {
      return query.addWhereClause(
        IdWhereClause.greaterThan(lower: id, includeLower: include),
      );
    });
  }

  QueryBuilder<Person, Person, QAfterWhereClause> idLessThan(Id id,
      {bool include = false}) {
    return QueryBuilder.apply(this, (query) {
      return query.addWhereClause(
        IdWhereClause.lessThan(upper: id, includeUpper: include),
      );
    });
  }

  QueryBuilder<Person, Person, QAfterWhereClause> idBetween(
    Id lowerId,
    Id upperId, {
    bool includeLower = true,
    bool includeUpper = true,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addWhereClause(IdWhereClause.between(
        lower: lowerId,
        includeLower: includeLower,
        upper: upperId,
        includeUpper: includeUpper,
      ));
    });
  }
}

extension PersonQueryFilter on QueryBuilder<Person, Person, QFilterCondition> {
  QueryBuilder<Person, Person, QAfterFilterCondition> idEqualTo(Id value) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.equalTo(
        property: r'id',
        value: value,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> idGreaterThan(
    Id value, {
    bool include = false,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.greaterThan(
        include: include,
        property: r'id',
        value: value,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> idLessThan(
    Id value, {
    bool include = false,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.lessThan(
        include: include,
        property: r'id',
        value: value,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> idBetween(
    Id lower,
    Id upper, {
    bool includeLower = true,
    bool includeUpper = true,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.between(
        property: r'id',
        lower: lower,
        includeLower: includeLower,
        upper: upper,
        includeUpper: includeUpper,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameIsNull() {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(const FilterCondition.isNull(
        property: r'name',
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameIsNotNull() {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(const FilterCondition.isNotNull(
        property: r'name',
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameEqualTo(
    String? value, {
    bool caseSensitive = true,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.equalTo(
        property: r'name',
        value: value,
        caseSensitive: caseSensitive,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameGreaterThan(
    String? value, {
    bool include = false,
    bool caseSensitive = true,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.greaterThan(
        include: include,
        property: r'name',
        value: value,
        caseSensitive: caseSensitive,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameLessThan(
    String? value, {
    bool include = false,
    bool caseSensitive = true,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.lessThan(
        include: include,
        property: r'name',
        value: value,
        caseSensitive: caseSensitive,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameBetween(
    String? lower,
    String? upper, {
    bool includeLower = true,
    bool includeUpper = true,
    bool caseSensitive = true,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.between(
        property: r'name',
        lower: lower,
        includeLower: includeLower,
        upper: upper,
        includeUpper: includeUpper,
        caseSensitive: caseSensitive,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameStartsWith(
    String value, {
    bool caseSensitive = true,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.startsWith(
        property: r'name',
        value: value,
        caseSensitive: caseSensitive,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameEndsWith(
    String value, {
    bool caseSensitive = true,
  }) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.endsWith(
        property: r'name',
        value: value,
        caseSensitive: caseSensitive,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameContains(String value,
      {bool caseSensitive = true}) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.contains(
        property: r'name',
        value: value,
        caseSensitive: caseSensitive,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameMatches(
      String pattern,
      {bool caseSensitive = true}) {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.matches(
        property: r'name',
        wildcard: pattern,
        caseSensitive: caseSensitive,
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameIsEmpty() {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.equalTo(
        property: r'name',
        value: '',
      ));
    });
  }

  QueryBuilder<Person, Person, QAfterFilterCondition> nameIsNotEmpty() {
    return QueryBuilder.apply(this, (query) {
      return query.addFilterCondition(FilterCondition.greaterThan(
        property: r'name',
        value: '',
      ));
    });
  }
}

extension PersonQueryObject on QueryBuilder<Person, Person, QFilterCondition> {}

extension PersonQueryLinks on QueryBuilder<Person, Person, QFilterCondition> {}

extension PersonQuerySortBy on QueryBuilder<Person, Person, QSortBy> {
  QueryBuilder<Person, Person, QAfterSortBy> sortByName() {
    return QueryBuilder.apply(this, (query) {
      return query.addSortBy(r'name', Sort.asc);
    });
  }

  QueryBuilder<Person, Person, QAfterSortBy> sortByNameDesc() {
    return QueryBuilder.apply(this, (query) {
      return query.addSortBy(r'name', Sort.desc);
    });
  }
}

extension PersonQuerySortThenBy on QueryBuilder<Person, Person, QSortThenBy> {
  QueryBuilder<Person, Person, QAfterSortBy> thenById() {
    return QueryBuilder.apply(this, (query) {
      return query.addSortBy(r'id', Sort.asc);
    });
  }

  QueryBuilder<Person, Person, QAfterSortBy> thenByIdDesc() {
    return QueryBuilder.apply(this, (query) {
      return query.addSortBy(r'id', Sort.desc);
    });
  }

  QueryBuilder<Person, Person, QAfterSortBy> thenByName() {
    return QueryBuilder.apply(this, (query) {
      return query.addSortBy(r'name', Sort.asc);
    });
  }

  QueryBuilder<Person, Person, QAfterSortBy> thenByNameDesc() {
    return QueryBuilder.apply(this, (query) {
      return query.addSortBy(r'name', Sort.desc);
    });
  }
}

extension PersonQueryWhereDistinct on QueryBuilder<Person, Person, QDistinct> {
  QueryBuilder<Person, Person, QDistinct> distinctByName(
      {bool caseSensitive = true}) {
    return QueryBuilder.apply(this, (query) {
      return query.addDistinctBy(r'name', caseSensitive: caseSensitive);
    });
  }
}

extension PersonQueryProperty on QueryBuilder<Person, Person, QQueryProperty> {
  QueryBuilder<Person, int, QQueryOperations> idProperty() {
    return QueryBuilder.apply(this, (query) {
      return query.addPropertyName(r'id');
    });
  }

  QueryBuilder<Person, String?, QQueryOperations> nameProperty() {
    return QueryBuilder.apply(this, (query) {
      return query.addPropertyName(r'name');
    });
  }
}

入力ページを作る

main.dartに入力するページとIsarに接続する設定を書いたコードを書いております。

main.dart

import 'package:flutter/material.dart';
import 'package:isar/isar.dart';
import 'package:isar_app/model/person.dart';
import 'package:isar_app/view.dart';
import 'package:path_provider/path_provider.dart';

void main() async {
  // Isarの初期化
  WidgetsFlutterBinding.ensureInitialized();
  // アプリのドキュメントディレクトリを取得
  final dir = await getApplicationDocumentsDirectory();
  final isar = await Isar.open(
    [PersonSchema],
    directory: dir.path,
  );

  runApp(MyApp(isar: isar));
}

class MyApp extends StatelessWidget {
  final Isar isar;

  MyApp({required this.isar});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Memo App',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: AddPage(isar: isar),
    );
  }
}

class AddPage extends StatefulWidget {
  const AddPage({Key? key, required this.isar}) : super(key: key);

  final Isar isar;

  @override
  State<AddPage> createState() => _AddPageState();
}

class _AddPageState extends State<AddPage> {
  final nameController = TextEditingController();

  @override
  void dispose() {
    nameController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('メモ追加'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            TextField(
              controller: nameController,
            ),
            ElevatedButton(
                onPressed: () async {
                  // Personクラスのインスタンスを作成
                  final person = Person()..name = nameController.text;
                  // 入力後にテキストフィールドを空にする
                  nameController.clear();
                  // widgetとは、StatefulWidgetのこと
                  // widget.isarで、StatefulWidgetのisarを参照できる
                  await widget.isar.writeTxn(() async {
                    await widget.isar.persons.put(person);
                  });
                },
                child: const Text('追加')),
            const SizedBox(height: 20),
            ElevatedButton(onPressed: () {
              Navigator.of(context).push(
                MaterialPageRoute(
                  builder: (context) => ViewPage(isar: widget.isar),
                ),
              );
            }, child: const Text('一覧へ'))
          ],
        ),
      ),
    );
  }
}

データの表示と削除

保存したデータの確認と削除ができるページです。

view.dart

import 'package:flutter/material.dart';
import 'package:isar/isar.dart';
import 'package:isar_app/model/person.dart';

class ViewPage extends StatefulWidget {
  final Isar isar;// Isarのインスタンスを受け取るための変数

  ViewPage({required this.isar});

  @override
  _ViewPageState createState() => _ViewPageState();
}

class _ViewPageState extends State<ViewPage> {
  List<Person> persons = []; // personsはデータベースの中身を取得するための変数

  // initStateを使うと、画面が表示される前にデータベースの中身を取得できます。
  @override
  void initState() {
    super.initState();
    loadData();
  }
  // データベースの中身を取得する関数
  Future<void> loadData() async {
    final data = await widget.isar.persons.where().findAll();
    setState(() {
      persons = data;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('データを表示')),
      body: ListView.builder(
        itemCount: persons.length,
        itemBuilder: (context, index) {
          final person = persons[index];
          return ListTile(
            title: Text(person.name ?? "値が入ってません"),
            trailing: IconButton(
              icon: const Icon(Icons.delete),
              onPressed: () async {
                // ここでデータベースから削除しています
                await widget.isar.writeTxn(() async {
                  await widget.isar.persons.delete(person.id);
                });
                await loadData();
              },
            )
          );
        },
      ),
    );
  }
}