Flutter应用内查询插件in_app_query的使用

发布于 1周前 作者 songsunli 来自 Flutter

Flutter应用内查询插件in_app_query的使用

在本示例中，我们将详细介绍如何使用 in_app_query 插件进行数据查询。此插件允许你在 Flutter 应用中执行复杂的数据查询操作。

引入包

首先，你需要在 pubspec.yaml 文件中添加 in_app_query 依赖：

dependencies:
  in_app_query: ^1.0.0

然后运行 flutter pub get 来安装依赖。

示例代码

import 'package:flutter/material.dart';
import 'package:in_app_query/in_app_query.dart';

void main() {
  List<Map<String, dynamic>> data = [
    {
      "id": "id_1",
      'username': 'daniel_white',
      'email': 'daniel_white@example.com',
      'age': 43,
      'country': 'India'
    },
    {
      "id": "id_2",
      'username': 'olivia_adams',
      'email': 'olivia_adams@hotmail.com',
      'age': 57,
      'country': 'Japan'
    },
    {
      "id": "id_3",
      'username': 'olivia_adams',
      'email': 'olivia_adams@test.com',
      'age': 36,
      'country': 'Brazil'
    },
    {
      "id": "id_4",
      'username': 'olivia_adams',
      'email': 'olivia_adams@demo.com',
      'age': 53,
      'country': 'Japan'
    },
    {
      "id": "id_5",
      'username': 'peter_brown',
      'email': 'peter_brown@gmail.com',
      'age': 57,
      'country': 'China'
    },
    {
      "id": "id_6",
      'username': 'olivia_adams',
      'email': 'olivia_adams@yahoo.com',
      'age': 30,
      'country': 'Brazil'
    },
    {
      "id": "id_7",
      'username': 'emma_smith',
      'email': 'emma_smith@example.com',
      'age': 49,
      'country': 'Germany'
    },
    {
      "id": "id_8",
      'username': 'olivia_adams',
      'email': 'olivia_adams@demo.com',
      'age': 53,
      'country': 'Canada'
    },
    {
      "id": "id_9",
      'username': 'peter_brown',
      'email': 'peter_brown@hotmail.com',
      'age': 65,
      'country': 'Brazil'
    },
    {
      "id": "id_10",
      'username': 'sarah_carter',
      'email': 'sarah_carter@gmail.com',
      'age': 55,
      'country': 'Japan'
    },
    {
      "id": "id_11",
      'username': null,
      'email': 'sarah_carter@gmail.com',
      'age': 55,
      'country': 'Japan'
    },
    {
      "id": "id_12",
      'username': 'olivia_adams',
      'email': 'olivia_adams@demo.com',
      'age': null,
      'country': 'US'
    },
    {
      "id": "id_13",
      'username': 'olivia_adams',
      'email': 'olivia_adams@yahoo.com',
      'age': 53,
      'country': 'Australia'
    },
  ];
  _queryTest(data);
  _sortingTest(data);
  _selectionTest();
  _pagination(data);
  runApp(const MyApp());
}

void _queryTest(List<Map<String, dynamic>> data) {
  // 简单查询
  var simple = QueryBuilder(data)
      .where('username', isEqualTo: "olivia_adams")
      .where('age', isLessThanOrEqualTo: 50)
      .build();

  simple.output(
      "Query output(simple): Query by username == olivia_adams and age <= 50");

  // 复杂查询
  var complex = QueryBuilder(data)
      .where(const Filter.or([
        Filter("age", isEqualTo: 30),
        Filter('age', isEqualTo: 53),
        Filter('age', isEqualTo: 63),
        Filter('country', isEqualTo: "Japan"),
      ]))
      .where(const Filter.and([
        Filter('country', isEqualTo: "Japan"),
        Filter('username', isEqualTo: "olivia_adams"),
      ]))
      .build();

  complex.output("Query output(filter): Query with OR and AND condition");
}

void _sortingTest(List<Map<String, dynamic>> data) {
  var result = QueryBuilder(data)
      .orderBy("username")
      .orderBy("email")
      .orderBy("age", descending: true)
      .orderBy("country")
      .build();

  result.output(
      "Sorted output: Sorted by username(asc), email(asc), age(des) and country(asc)");
}

void _selectionTest() {
  List<Map<String, dynamic>> data = [
    {'username': 'alice', 'age': 25, 'country': 'USA'},
    {'username': 'bob', 'age': 30, 'country': 'Canada'},
    {'username': 'charlie', 'age': 35, 'country': 'Australia'},
    {'username': 'daniel', 'age': 40, 'country': 'UK'},
    {'username': 'emma', 'age': 45, 'country': 'Germany'}
  ];

  // 使用QueryBuilder进行endAt选择
  var endAt = QueryBuilder(data).endAt(['daniel']).build();
  endAt.output("Selection output: endAt");

  // 使用QueryBuilder进行startAtDocument选择
  var endAtDocument = QueryBuilder(data).endAtDocument(
      {'username': 'daniel', 'age': 40, 'country': 'UK'}).build();
  endAtDocument.output("Selection output: endAtDocument");

  // 使用QueryBuilder进行endBefore选择
  var endBefore = QueryBuilder(data).endBefore(['daniel']).build();
  endBefore.output("Selection output: endBefore");

  // 使用QueryBuilder进行endBeforeDocument选择
  var endBeforeDocument = QueryBuilder(data).endBeforeDocument(
      {'username': 'daniel', 'age': 40, 'country': 'UK'}).build();
  endBeforeDocument.output("Selection output: endBeforeDocument");

  // 使用QueryBuilder进行startAt选择
  var startAt = QueryBuilder(data).startAt(['bob']).build();
  startAt.output("Selection output: startAt");

  // 使用QueryBuilder进行startAtDocument选择
  var startAtDocument = QueryBuilder(data).startAtDocument(
      {'username': 'bob', 'age': 30, 'country': 'Canada'}).build();
  startAtDocument.output("Selection output: startAtDocument");

  // 使用QueryBuilder进行startAfter选择
  var startAfter = QueryBuilder(data).startAfter(['bob']).build();
  startAfter.output("Selection output: startAfter");

  // 使用QueryBuilder进行startAfterDocument选择
  var startAfterDocument = QueryBuilder(data).startAfterDocument(
      {'username': 'bob', 'age': 30, 'country': 'Canada'}).build();
  startAfterDocument.output("Selection output: startAfterDocument");

  // 使用QueryBuilder进行startAt和endAt选择
  var startAtEndAt = QueryBuilder(data).startAt(
    ["bob", 30],
  ).endAt(
    ['daniel', 40],
  ).build();
  startAtEndAt.output("Selection output: startAtEndAt");

  // 使用QueryBuilder进行startAtDocument和endAtDocument选择
  var startAtDocumentEndAtDocument = QueryBuilder(data).startAtDocument(
    {'username': 'bob', 'age': 30, 'country': 'Canada'},
  ).endAtDocument(
    {'username': 'daniel', 'age': 40, 'country': 'UK'},
  ).build();
  startAtDocumentEndAtDocument
      .output("Selection output: startAtDocumentEndAtDocument");

  // 使用QueryBuilder进行startAfter和endBefore选择
  var startAfterEndBefore = QueryBuilder(data).startAfter(
    ["bob", 30],
  ).endBefore(
    ['daniel', 40],
  ).build();
  startAfterEndBefore.output("Selection output: startAfterEndBefore");

  // 使用QueryBuilder进行startAfterDocument和endBeforeDocument选择
  var startAfterDocumentEndBeforeDocument =
      QueryBuilder(data).startAfterDocument(
    {'username': 'bob', 'age': 30, 'country': 'Canada'},
  ).endBeforeDocument(
    {'username': 'daniel', 'age': 40, 'country': 'UK'},
  ).build();
  startAfterDocumentEndBeforeDocument
      .output("Selection output: startAfterDocumentEndBeforeDocument");
}

void _pagination(List<Map<String, dynamic>> data) {
  // 简单分页
  var simple = QueryBuilder(data)
      .where("username", isNull: false)
      .where("country", isEqualTo: "Japan")
      .orderBy("age", descending: true)
      .limit(3)
      .build();
  simple.output("Pagination output: simple");

  // 复杂分页
  var pagination = QueryBuilder(data)
      .where("username", isNull: false)
      .startAfter(["id_3"])
      .limit(3)
      .build();
  pagination.output("Pagination output: selection");
}

extension on List {
  void output(String name) {
    print('\n$name');
    forEach(print);
  }
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }
}

代码解释

  1. 简单查询：

    var simple = QueryBuilder(data)
    .where('username', isEqualTo: "olivia_adams")
    .where('age', isLessThanOrEqualTo: 50)
    .build();

  2. 复杂查询：

    var complex = QueryBuilder(data)
    .where(const Filter.or([
      Filter("age", isEqualTo: 30),
      Filter('age', isEqualTo: 53),
      Filter('age', isEqualTo: 63),
      Filter('country', isEqualTo: "Japan"),
    ]))
    .where(const Filter.and([
      Filter('country', isEqualTo: "Japan"),
      Filter('username', isEqualTo: "olivia_adams"),
    ]))
    .build();

  3. 排序：

    var result = QueryBuilder(data)
    .orderBy("username")
    .orderBy("email")
    .orderBy("age", descending: true)
    .orderBy("country")
    .build();

  4. 选择：

    var endAt = QueryBuilder(data).endAt(['daniel']).build();

  5. 分页：

    var simple = QueryBuilder(data)
    .where("username", isNull: false)
    .where("country", isEqualTo: "Japan")
    .orderBy("age", descending: true)
    .limit(3)
    .build();

更多关于Flutter应用内查询插件in_app_query的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html

1 回复

更多关于Flutter应用内查询插件in_app_query的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html


当然，以下是如何在Flutter应用中使用in_app_query插件的示例代码。in_app_query插件允许开发者在应用内查询和管理用户的订阅和购买信息。请注意，为了使用此插件，你需要在pubspec.yaml文件中添加依赖，并确保你已经设置好Google Play Billing Library和App Store Connect的相关配置。

1. 添加依赖

首先，在你的pubspec.yaml文件中添加in_app_query依赖：

dependencies:
  flutter:
    sdk: flutter
  in_app_query: ^最新版本号  # 请替换为实际的最新版本号

然后运行flutter pub get来安装依赖。

2. 导入插件

在你的Dart文件中导入in_app_query插件：

import 'package:in_app_query/in_app_query.dart';

3. 初始化插件

在应用的入口文件（通常是main.dart）中初始化插件：

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await InAppQuery.initialize();  // 初始化插件
  runApp(MyApp());
}

4. 查询购买和订阅信息

以下是一个简单的例子，展示如何查询用户的购买和订阅信息：

import 'package:flutter/material.dart';
import 'package:in_app_query/in_app_query.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await InAppQuery.initialize();
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('In-App Query Example'),
        ),
        body: QueryPurchasesScreen(),
      ),
    );
  }
}

class QueryPurchasesScreen extends StatefulWidget {
  @override
  _QueryPurchasesScreenState createState() => _QueryPurchasesScreenState();
}

class _QueryPurchasesScreenState extends State<QueryPurchasesScreen> {
  List<Purchase> _purchases = [];

  @override
  void initState() {
    super.initState();
    _queryPurchases();
  }

  Future<void> _queryPurchases() async {
    try {
      List<Purchase> purchases = await InAppQuery.queryPurchases();
      setState(() {
        _purchases = purchases;
      });
    } catch (e) {
      print("Error querying purchases: $e");
    }
  }

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.all(16.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            'Your Purchases:',
            style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
          ),
          SizedBox(height: 16),
          Expanded(
            child: ListView.builder(
              itemCount: _purchases.length,
              itemBuilder: (context, index) {
                Purchase purchase = _purchases[index];
                return Padding(
                  padding: const EdgeInsets.symmetric(vertical: 8.0),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Text('Product ID: ${purchase.productId}'),
                      Text('Purchase Token: ${purchase.purchaseToken}'),
                      Text('Purchase Date: ${purchase.purchaseDate}'),
                      Text('Is Auto Renewing: ${purchase.isAutoRenewing}'),
                    ],
                  ),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}

在这个示例中，我们创建了一个简单的Flutter应用，该应用在启动时查询用户的购买信息，并在UI中显示这些信息。

注意事项

  1. 权限和配置：确保你的应用已经正确配置了Google Play Billing Library（对于Android）和App Store Connect（对于iOS）。
  2. 错误处理：在生产环境中，请添加适当的错误处理和用户反馈。
  3. 测试：在发布前，请使用测试账号在沙盒环境中充分测试购买流程。

希望这个示例能帮助你在Flutter应用中成功使用in_app_query插件！

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