Flutter并发执行插件concurrent_executor的使用

Flutter并发执行插件concurrent_executor的使用

使用

一个简单的使用示例：

import 'dart:io';
import 'dart:isolate';

import 'package:concurrent_executor/concurrent_executor.dart';

void main() async {
  // 创建一个可以同时运行3个任务的执行器
  var executor = await Executor.createExecutor(3);

  var foo = Foo();
  executor.submit(foo).then((value) => value, onError: (e, s) {
    print(e);
    print(s);
  });

  var res = executor.submit(foo);
  print(res);

  var foo2 = Foo2();
  var res222 = executor.submit(foo2);
  print(await res222);

  var res22 = executor.submit(foo2);
  print(await res22);

  var foo3 = Foo3();
  var res3 = executor.submit(foo3);
  print(res3);

  var res33 = executor.submit(foo3);
  print(res33);

  var foo33 = Foo3();
  var res333 = executor.submit(foo33);
  print(await res333);

  var foo4 = Foo4();
  foo4.stat = 'aaaaccc';
  var res44 = executor.submit(foo4);
  print(res44);

  var foo44 = Foo4();
  foo44.stat = 'vvvveee';
  var res444 = executor.submit(foo44);
  print(await res444);

  var foo5 = Foo5();
  foo5.stat = 99;
  var res5 = executor.submit(foo5);
  print(await res5);

  var foo6 = Foo6();
  foo6.stat = 'kkkkttt';
  var res6 = executor.submit(foo6);
  print(res6);

  // region pause
  var receivePort = ReceivePort();
  await Isolate.spawn(pause, receivePort.sendPort);
  await for (var _ in receivePort) {
    break;
  }
  print('pause close');
  receivePort.close();
  // endregion

  //await executor.close(CloseLevel.immediately);
  //executor.close(CloseLevel.immediately);
  //await executor.close(CloseLevel.afterRunningFinished);
  // close default is afterRunningFinished
  await executor.close();
  //await executor.close(CloseLevel.afterAllFinished);
  //executor.close(CloseLevel.afterAllFinished);
  print(
      'the following ${executor.unfinishedTasks.length} tasks has not executed completely:');
  print(executor.unfinishedTasks.map((e) => e.runtimeType));
}

// 定义不同的任务类
class Foo extends ConcurrentTask<void> {
  [@override](/user/override)
  void run() {
    print('${Isolate.current.debugName}-executeFoo');
    sleep(Duration(seconds: 1));
  }
}

class Foo2 extends ConcurrentTask<int> {
  [@override](/user/override)
  int run() {
    print('${Isolate.current.debugName}-executeFoo2');
    sleep(Duration(seconds: 1));
    return 3;
  }
}

class Foo3 extends ConcurrentTask<Future<int>> {
  [@override](/user/override)
  Future<int> run() async {
    print('${Isolate.current.debugName}-executeFoo3');
    return await Future.value(9);
  }
}

class Foo4 extends ConcurrentTask<int> {
  Object? stat = 888;

  [@override](/user/override)
  int run() {
    print('${Isolate.current.debugName}-executeFoo4-$stat');
    sleep(Duration(seconds: 1));
    return 344;
  }
}

class Foo5 extends ConcurrentTask<int> {
  var stat = 85288;

  [@override](/user/override)
  int run() {
    print('${Isolate.current.debugName}-executeFoo5-$stat');
    sleep(Duration(seconds: 1));
    return stat;
  }
}

class Foo6 extends ConcurrentTask<int> {
  String stat = '';

  [@override](/user/override)
  int run() {
    print('${Isolate.current.debugName}-executeFoo6-$stat');
    sleep(Duration(seconds: 1));
    return 6663;
  }
}

// 暂停执行的函数
void pause(SendPort message) {
  sleep(Duration(seconds: 1));
  message.send('close');
}

更多关于Flutter并发执行插件concurrent_executor的使用的实战教程也可以访问 https://www.itying.com/category-92-b0.html

1 回复

更多关于Flutter并发执行插件concurrent_executor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中使用concurrent_executor插件来并发执行任务的示例代码。concurrent_executor插件允许你并发地执行多个Future任务，并收集它们的结果。

首先，确保你已经在pubspec.yaml文件中添加了concurrent_executor依赖：

dependencies:
  flutter:
    sdk: flutter
  concurrent_executor: ^latest_version  # 请替换为最新的版本号

然后运行flutter pub get来安装依赖。

以下是一个完整的Flutter应用程序示例，它演示了如何使用concurrent_executor来并发执行一些任务：

import 'package:flutter/material.dart';
import 'package:concurrent_executor/concurrent_executor.dart';
import 'dart:async';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Concurrent Executor Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String _result = 'Press the button to start tasks';

  Future<void> _executeTasks() async {
    // 创建一个ConcurrentExecutor实例
    final executor = ConcurrentExecutor();

    // 定义一些模拟的异步任务
    Future<String> task1() async {
      await Future.delayed(Duration(seconds: 2));
      return 'Task 1 completed';
    }

    Future<String> task2() async {
      await Future.delayed(Duration(seconds: 3));
      return 'Task 2 completed';
    }

    Future<String> task3() async {
      await Future.delayed(Duration(seconds: 1));
      return 'Task 3 completed';
    }

    // 使用ConcurrentExecutor并发执行任务
    List<Future<String>> tasks = [task1(), task2(), task3()];
    List<String> results = await executor.executeAll(tasks);

    // 更新UI
    setState(() {
      _result = results.join('\n');
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Concurrent Executor Demo'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              _result,
              style: TextStyle(fontSize: 20),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: _executeTasks,
              child: Text('Execute Tasks'),
            ),
          ],
        ),
      ),
    );
  }
}

在这个示例中，我们创建了三个模拟的异步任务，每个任务都会延迟一段时间然后返回一个字符串。我们使用ConcurrentExecutor的executeAll方法来并发执行这些任务，并收集它们的结果。最后，我们将结果显示在UI上。

当你运行这个应用程序并点击“Execute Tasks”按钮时，你会看到所有任务并发执行，并在UI上按顺序显示它们的结果。

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