Flutter : sqliteの利用

Flutter + Firebase でアプリ作成のためのパーツあつめ。

1.ここまでに確認したこと

2.今回の確認

sqliteの利用

import 'package:path/path.dart';
import 'package:sqflite/sqflite.dart';
class DbTest {
  void firstDbTest() async {
    // OSなど環境別のDBディレクトリパスを取得する
    var dbPath = await getDatabasesPath();
    // DBファイルパス
    dbPath = join(dbPath, 'demo.db');
    print("DB Path $dbPath");

    var helper = MemoProvider();
    Database db = await helper.open(dbPath);

    print("DB: ${db.toString()}");

    var list = await helper.getAll();
    if (list.length < 10) {
      var newMemo = Memo();
      newMemo.memo = "Memo ${DateTime.now()}";
      helper.insert(newMemo);
    }

    for(Memo memo in list) {
      print("MEMO : ${memo.toMap().toString()}");
    }
  }
}

class MemoMeta {
  static String tableName = "Memo";
  static String columnId = "_id";
  static String columnMemo = "memo";

  static List<String> columns() {
    return [columnId, columnMemo];
  }
}

class Memo {
  int id;
  String memo;

  Map<String, dynamic> toMap() {
    var map = <String, dynamic> {
      MemoMeta.columnMemo: memo
    };
    if (id != null) {
      map[MemoMeta.columnId] = id;
    }
    return map;
  }

  Memo();

  Memo.fromMap(Map<String, dynamic> map) {
    id = map[MemoMeta.columnId];
    memo = map[MemoMeta.columnMemo];
  }
}

class MemoProvider {
  Database db;

  Future<Database> open(String path) async {
    var ddl = """
create table ${MemoMeta.tableName} (
  ${MemoMeta.columnId} integer primary key autoincrement,
  ${MemoMeta.columnMemo} text not null )
""";
    print("DDL: $ddl");

    db = await openDatabase(path, version: 1,
      onCreate: (Database db, int version) async {
        await db.execute(ddl);
      }
    );
    return db;
  }

  Future<Memo> insert(Memo memo) async {
    memo.id = await db.insert(MemoMeta.tableName, memo.toMap());
    return memo;
  }

  Future<List<Memo>> getAll() async {
    List<Map> maps = await db.query(
        MemoMeta.tableName,
        columns : MemoMeta.columns());
    var list = new List<Memo>();
    for(Map map in maps) {
      list.add(Memo.fromMap(map));
    }
    return list;
  }

  Future<Memo> findById(int id) async {
    List<Map> maps = await db.query(MemoMeta.tableName,
      columns: MemoMeta.columns(),
      where: '${MemoMeta.columnId} = ?',
      whereArgs: [id]);
    if (maps.length > 0) {
      return Memo.fromMap(maps.first);
    }
    return null;
  }

  Future<int> delete(int id) async {
    return await db.delete(
        MemoMeta.tableName, where: '${MemoMeta.columnId} = ?', whereArgs: [id]);
  }

  Future<int> update(Memo memo) async {
    return await db.update(MemoMeta.tableName, memo.toMap(),
      where: '${MemoMeta.columnId} = ?', whereArgs: [memo.id]);
  }

  Future close() async => db.close();

}

ログに出力された。

I/flutter ( 3116): DB Path /data/user/0/info.typea.favo_phrase_trial/databases/demo.db
I/flutter ( 3116): DDL: create table Memo (
I/flutter ( 3116):   _id integer primary key autoincrement,
I/flutter ( 3116):   memo text not null )
I/flutter ( 3116): DB: 2 /data/user/0/info.typea.favo_phrase_trial/databases/demo.db
V/AudioManager( 3116): playSoundEffect   effectType: 0
V/AudioManager( 3116): querySoundEffectsEnabled...
I/flutter ( 3116): MEMO : {memo: Memo 2019-12-09 21:18:12.816597, _id: 1}
I/flutter ( 3116): MEMO : {memo: Memo 2019-12-09 21:18:17.761803, _id: 2}