Question

如何在SQLite上保存列表数据？，没有列表数据，我知道如何存储。但列出数据我不知道该怎么做。 API附带了1000多个数据。我需要一次存储所有数据的缓存。

另一个问题，存储数据后，我需要每1小时检查一次后端，如果服务器中有新数据，则需要更新本地数据。怎么做？

这是我的模型课，

class AssetRegister {
  final List<Data> data;

  AssetRegister({this.data});

  factory AssetRegister.fromJson(Map<String, dynamic> json) {
    var list = json['data'] as List;
    print(list.runtimeType);
    List<Data> assetList = list.map((i) => Data.fromJson(i)).toList();

    return AssetRegister(data: assetList);
  }
  Map<String, dynamic> toMap() {
    return {
      'data': data,
    };
  }
}

class Data {
  final int i;
  final String d;
  final int c;
  final int u;
  final double p;
  final int a;

  Data({this.i, this.d, this.c, this.u, this.p, this.a});

  factory Data.fromJson(Map<String, dynamic> json) {
    return Data(
      i: json['i'],
      d: json['d'],
      c: json['c'],
      u: json['u'],
      p: json['p'],
      a: json['a'],
    );
  }
}

我尝试过，但是没有用。错误消息是“数据实例”。这是我的代码。

class HelperRegister {
  static final HelperRegister _instance =  HelperRegister.internal();
  factory HelperRegister() => _instance;
  static Database _db;

  Future<Database> get db1 async {
    if (_db != null) return _db;
    _db = await initDb();
    return _db;
  }

  HelperRegister.internal();

  initDb() async {
    io.Directory documentsDirectory = await getApplicationDocumentsDirectory();
    String path = join(documentsDirectory.path, "RegisterDB.db");
    var theDb = await openDatabase(path, version: 1, onCreate: _onCreate);
    return theDb;
  }

  void _onCreate(Database db, int version) async {
    // When creating the db, create the table
    await db.execute(
        "CREATE TABLE registerTable(i INTEGER PRIMARY KEY, d TEXT, c INTEGER, u INTEGER, p DOUBLE, a INTEGER)");
  }




  databaseTokenTesting(String tokenModel, String refreshTokenModel,
      String method) async {
    final database = openDatabase(
      join(await getDatabasesPath(), 'RegisterDB.db'),
      onCreate: (db, version) {
        return db.execute(
          "CREATE TABLE registerTable(i INTEGER PRIMARY KEY, d TEXT, c INTEGER, u INTEGER, p DOUBLE, a INTEGER)",
        );
      },
      version: 1,
    );
  }

  Future<void> insert(AssetRegister assetregister) async {
    var db = await db1;
    await db.insert(
      'registerTable',
      assetregister.toMap(),
      conflictAlgorithm: ConflictAlgorithm.replace,
    );
  }

  Future<List<AssetRegister>> display() async {
    var db = await db1;
    final List<Map<String, dynamic>> maps = await db.query('registerTable');

    return List.generate(maps.length, (i) {
      return AssetRegister(
        data: maps[i]['data'],
      );
    });
  }

  Future<void> update(AssetRegister assetregister) async {
    var db = await db1;
    await db.update(
      'tokenTable',
      assetregister.toMap(),
      where: "i = ?",
      whereArgs: [assetregister.data[1].i],
    );
  }
}

这是我的功能。

storeRegister(String url,String token) async {
 final response = await http.get(
    '${url}/v1.0/Register',
    headers: {'Authorization': 'Bearer ${token}'},);
  final jsonResponse = json.decode(response.body);
  AssetRegister model = AssetRegister.fromJson(jsonResponse);
  await HelperRegister().insert(model);
}

这是我的json

    {
        "data": [
            {
                "i": 1,
                "d": "Guest Rooms",
                "c": 1,
                "u": 1,
                "p": 1.1,
                "a": null
            },
            {
                "i": 5,
                "d": "Front of House",
                "c": 1,
                "u": 1,
                "p": 1.2,
                "a": null
            },
...
        ]
    }

如何使用Lists json存储本地（sqlite）嵌套结构？

0 个答案: