Flutter队列管理插件queuekit的使用

Flutter队列管理插件queuekit的使用

Queuekit 是一个用于 Dart 和 Flutter 应用程序的任务队列库。它支持跨应用重启任务的持久化。

示例代码

以下是使用 queuekit 的完整示例代码：

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:queuekit/queuekit.dart';
import 'package:shared_preferences/shared_preferences.dart';

// 创建一个队列开始监听器
final startListenable = QueueStartListenable();

// 定义一个持久化的队列
late final HydratedQueue queue;

// 自定义事件序列化器
final exampleEventSerializer = JsonSerializer(
  fromJson: (json) {
    return ExampleEvent()
      ..retryConfig = linearRetryConfigSerializer.fromJson(
        json['retryConfig'] as Map<String, dynamic>,
      );
  },
  toJson: (event) {
    return {
      'retryConfig': linearRetryConfigSerializer.toJson(event.retryConfig!),
    };
  },
);

// 定义一个示例事件类
class ExampleEvent extends Event<String> {
  @override
  String get id => 'id';

  @override
  String get type => 'ExampleEvent';

  @override
  LinearRetryConfig? retryConfig = LinearRetryConfig(maxRetries: 10, delay: const Duration(seconds: 1));

  @override
  Future<String> run() {
    return Future.delayed(const Duration(seconds: 1), () => 'Hello World!');
  }
}

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  // 初始化SharedPreferences
  final prefs = await SharedPreferences.getInstance();
  
  // 创建持久化的队列实例
  queue = HydratedQueue(
    startListenable,
    eventSerializers: {
      'ExampleEvent': (
        fromJson: exampleEventSerializer.fromJson,
        toJson: (event) => exampleEventSerializer.toJson(event as ExampleEvent),
      ),
    },
    saveCurrentQueue: (data) async {
      await prefs.setString('currentQueue', data);
    },
    hydrateCurrentQueue: () {
      return prefs.getString('currentQueue');
    },
    saveRetryQueue: (data) async {
      await prefs.setString('retryQueue', data);
    },
    hydrateRetryQueue: () {
      return prefs.getString('retryQueue');
    },
  );

  // 恢复队列状态
  await queue.hydrate();
  startListenable.start();

  // 启动应用
  runApp(const MainApp());
}

// 主应用类
class MainApp extends StatefulWidget {
  const MainApp({super.key});

  @override
  State<MainApp> createState() => _MainAppState();
}

// 主应用状态类
class _MainAppState extends State<MainApp> {
  late final StreamSubscription subscription;
  final data = <String>[];

  @override
  void initState() {
    super.initState();
    // 监听队列事件
    subscription = queue.listenWhere<ExampleEvent, String>((params) {
      setState(() {
        data.add(params.result);
      });
    });
  }

  @override
  void dispose() {
    // 取消订阅
    subscription.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              if (data.isEmpty) const Text('按按钮添加事件'),
              for (final item in data) Text(item),
            ],
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () {
            // 添加事件到队列
            queue.add(ExampleEvent());
          },
          child: const Icon(Icons.add),
        ),
      ),
    );
  }
}

代码解释

1. 导入必要的包

   import 'dart:async';
   import 'package:flutter/material.dart';
   import 'package:queuekit/queuekit.dart';
   import 'package:shared_preferences/shared_preferences.dart';
   

2. 创建队列开始监听器

   final startListenable = QueueStartListenable();
   

3. 初始化SharedPreferences

   final prefs = await SharedPreferences.getInstance();
   

4. 创建持久化的队列实例

   queue = HydratedQueue(
     startListenable,
     eventSerializers: {
       'ExampleEvent': (
         fromJson: exampleEventSerializer.fromJson,
         toJson: (event) => exampleEventSerializer.toJson(event as ExampleEvent),
       ),
     },
     saveCurrentQueue: (data) async {
       await prefs.setString('currentQueue', data);
     },
     hydrateCurrentQueue: () {
       return prefs.getString('currentQueue');
     },
     saveRetryQueue: (data) async {
       await prefs.setString('retryQueue', data);
     },
     hydrateRetryQueue: () {
       return prefs.getString('retryQueue');
     },
   );
   

5. 恢复队列状态

   await queue.hydrate();
   startListenable.start();
   

6. 监听队列事件

   subscription = queue.listenWhere<ExampleEvent, String>((params) {
     setState(() {
       data.add(params.result);
     });
   });
   

7. 添加事件到队列

   queue.add(ExampleEvent());
   

8. 构建UI

   return MaterialApp(
     home: Scaffold(
       body: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: [
             if (data.isEmpty) const Text('按按钮添加事件'),
             for (final item in data) Text(item),
           ],
         ),
       ),
       floatingActionButton: FloatingActionButton(
         onPressed: () {
           queue.add(ExampleEvent());
         },
         child: const Icon(Icons.add),
       ),
     ),
   );