firebase - firebase 数据库创建的 Flutter 数据类

Question

请问如何在 flutter 中使用 firebase 数据库创建一个数据类，数据会立即加载到应用程序的第一页？

    import 'package:dnow/model/company.dart';
    import 'package:firebase_database/firebase_database.dart';

    class RepoData {

      static final Company bawp = new Company(
          name: 'King',
          about: 'Selling Food',
          backdropPhoto: 'assets/hk.jpg',

          shop: <Shop>[
            new Shop(
                shopName: 'ABC',
                thumbnail: 'assets/daofang.png',
                tel: "88776655",
                address: '23 Daisy street, Sydney'),

            new Shop(
                shopName: 'KKK',
                thumbnail: 'assets/fefew.png',
                tel: "88776655",
                address: '131 Man street, Sydney'),


          ],
          location: 'Sydney',
          logo: 'assets/logo.png',
          president: 'Grand Production House');
    }


  [1]: /image/DV3X0.png

Answer 1

假设这是你的类简化

Class Company {
 String name;
 String about;
 String backdropPhoto;
 String location;
 String logo;
 String president;
}

然后在您的应用程序的第一页中，您正在收听数据库并收到一个公司，类似这样

database.reference().child('companies').once().then((DataSnapshot snapshot) {
   //todo: parse snapshot
});

这里您从数据库接收一个 DataSnapshot 对象。您需要做的是将 DataSnapshot 解析为您的 Company 类。为此，您需要在 Company 类中创建自定义构造函数，如下所示

import 'package:firebase_database/firebase_database.dart';

Class Company {
 String name;
 String about;
 String backdropPhoto;
 String location;
 String logo;
 String president;

 Company.fromDb(DataSnapshot data) {
  name = data['name'];
  about = data['about'];
  backdropPhoto = data['backdropPhoto'];
  location = data['location'];
  logo = data['logo'];
  president = data['president'];
 }
}

最后，当您从 firebase 接收到文档时，您将调用此构造函数

database.reference().child('companies').once().then((DataSnapshot snapshot) {
    Company company = Company.fromDb(snapshot);
});

我只使用过 Firestore，但我认为它可能是这样工作的。希望对你有帮助