Flutter后台任务执行插件ui_background_task的使用

Flutter后台任务执行插件ui_background_task的使用

ui_background_task 是一个用于 Flutter iOS 平台的插件，用于开始和结束用户界面（UI）后台任务。它可以帮助在应用程序被推到后台后最多30秒内完成长时间运行的任务。

使用示例

以下是一个完整的示例，展示了如何在 Flutter 应用程序中使用 ui_background_task 插件来管理后台任务。

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

void main() {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  [@override](/user/override)
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> with WidgetsBindingObserver {
  int? _taskId;

  [@override](/user/override)
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('后台任务示例应用'),
        ),
        body: Center(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              ElevatedButton(
                  onPressed: () async {
                    _taskId = await UiBackgroundTask.instance.beginBackgroundTask();
                    setState(() {});
                  },
                  child: const Text('开始后台任务')),
              const SizedBox(
                width: 24,
              ),
              if (_taskId != null)
                ElevatedButton(
                  onPressed: () {
                    UiBackgroundTask.instance.endBackgroundTask(_taskId!);
                    setState(() {
                      _taskId = null;
                    });
                  },
                  child: Text(
                    '结束后台任务: $_taskId',
                  ),
                )
            ],
          ),
        ),
      ),
    );
  }

  [@override](/user/override)
  void dispose() {
    super.dispose();
    WidgetsBinding.instance.removeObserver(this);
  }

  [@override](/user/override)
  void didChangeAppLifecycleState(AppLifecycleState state) {
    super.didChangeAppLifecycleState(state);
    UiBackgroundTask.instance.appLifeCycleUpdate(state);
  }
}

代码解释

1. 导入必要的库

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

2. 创建主应用类

   void main() {
     runApp(const MyApp());
   }
   

3. 定义主应用状态类

   class MyApp extends StatefulWidget {
     const MyApp({Key? key}) : super(key: key);
   
     [@override](/user/override)
     State<MyApp> createState() => _MyAppState();
   }
   

4. 定义状态类并实现 WidgetsBindingObserver 接口

   class _MyAppState extends State<MyApp> with WidgetsBindingObserver {
     int? _taskId;
   

5. 初始化状态

   [@override](/user/override)
   void initState() {
     super.initState();
     WidgetsBinding.instance.addObserver(this);
   }
   

6. 构建应用UI

   [@override](/user/override)
   Widget build(BuildContext context) {
     return MaterialApp(
       home: Scaffold(
         appBar: AppBar(
           title: const Text('后台任务示例应用'),
         ),
         body: Center(
           child: Column(
             mainAxisSize: MainAxisSize.min,
             children: [
               ElevatedButton(
                   onPressed: () async {
                     _taskId = await UiBackgroundTask.instance.beginBackgroundTask();
                     setState(() {});
                   },
                   child: const Text('开始后台任务')),
               const SizedBox(
                 width: 24,
               ),
               if (_taskId != null)
                 ElevatedButton(
                   onPressed: () {
                     UiBackgroundTask.instance.endBackgroundTask(_taskId!);
                     setState(() {
                       _taskId = null;
                     });
                   },
                   child: Text(
                     '结束后台任务: $_taskId',
                   ),
                 )
             ],
           ),
         ),
       ),
     );
   }
   

7. 清理资源

   [@override](/user/override)
   void dispose() {
     super.dispose();
     WidgetsBinding.instance.removeObserver(this);
   }
   

8. 处理应用生命周期变化

   [@override](/user/override)
   void didChangeAppLifecycleState(AppLifecycleState state) {
     super.didChangeAppLifecycleState(state);
     UiBackgroundTask.instance.appLifeCycleUpdate(state);
   }