关于flutter:Flutter-Desktop-读取本地assets目录下的数据库db文件

一、增加第三方库

flutter pub add sqflite_common_ffi

二、在pubspec.yaml中配置assets

留神格局

assets:  - assets/xxx.db

三、初始化数据库
我的项目初始化当前会从根目录下的.dart_tool/sqflite_common_ffi/databases/xxx.db读取数据库文件，如果没有则把assets目录下的拷贝到该目录下。

  initialDatabase() async {    sqfliteFfiInit();    var databaseFactory = databaseFactoryFfi;    var databasesPath = await databaseFactory.getDatabasesPath();    var path = join(databasesPath, "express.db");    print(path);    var exists = await databaseFactory.databaseExists(path);    if (!exists) {      // Should happen only the first time you launch your application      print("Creating new copy from asset");      try {        await Directory(dirname(path)).create(recursive: true);      } catch (_) {}      // Copy from asset      ByteData data = await rootBundle.load('assets/express.db');      print(join('assets','express.db'));      // ByteData data = await rootBundle.load(join('assets','express.db'));      List<int> bytes = data.buffer.asUint8List(data.offsetInBytes, data.lengthInBytes);      // Write and flush the bytes written      await File(path).writeAsBytes(bytes, flush: true);    } else {      print("Opening existing database");    }    // open the database    this._db = await databaseFactory.openDatabase(path);    print(databasesPath);  }

四、查问数据

  // 查问  Future<List<UnitPrice>> queryPrice() async {    List<UnitPrice> priceList = [];    var result = await _db.query(table_name, where: 'id = ?', whereArgs: [1]);    return priceList;  }