Flutter可取消请求插件cancellable_requester的使用

Flutter可取消请求插件cancellable_requester的使用

在开发过程中，我们经常会遇到需要取消网络请求的情况。为了满足这一需求，可以使用cancellable_requester插件来管理可取消的网络请求。下面将详细介绍如何在Flutter项目中使用该插件。

示例代码

首先，在项目的pubspec.yaml文件中添加依赖：

dependencies:
  flutter:
    sdk: flutter
  dio: ^5.0.0  # 请根据实际情况选择合适的版本
  cancellable_requester: ^1.0.0  # 请根据实际情况选择合适的版本

然后，运行flutter pub get以安装这些依赖。

接下来，我们将展示如何在Flutter应用中使用cancellable_requester插件来发起一个可取消的网络请求，并展示如何取消它。

示例代码文件：example/lib/main.dart

import 'package:cancellable_requester/cancellable_requester.dart';
import 'package:dio/dio.dart';
import 'package:flutter/material.dart';

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

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

  // 这个小部件是你的应用程序的根。
  @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(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              '你已经点击了按钮次数：',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headlineMedium,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () async {
          var dio = Dio(
              BaseOptions(baseUrl: "https://jsonplaceholder.typicode.com/"));
          var res = dio.getCancellable("todos");
          print(RequestCancellable.tokens.length);
          var response = await res.response;
          print("response : ${response.data}");
          print(RequestCancellable.tokens.length);

          // 取消所有带有特定路径的请求
          RequestCancellable.cancellAll((token) => token.path == "todos");
        },
        tooltip: '增加',
        child: const Icon(Icons.add),
      ),
    );
  }
}

代码解释

1. 导入依赖

   import 'package:cancellable_requester/cancellable_requester.dart';
   import 'package:dio/dio.dart';
   import 'package:flutter/material.dart';
   

2. 定义主应用

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

3. 创建主页面

   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'),
       );
     }
   }
   

4. 创建首页

   class MyHomePage extends StatefulWidget {
     const MyHomePage({super.key, required this.title});
   
     final String title;
   
     @override
     State<MyHomePage> createState() => _MyHomePageState();
   }
   

5. 定义状态类

   class _MyHomePageState extends State<MyHomePage> {
     int _counter = 0;
   
     void _incrementCounter() {
       setState(() {
         _counter++;
       });
     }
   
     @override
     Widget build(BuildContext context) {
       return Scaffold(
         appBar: AppBar(
           backgroundColor: Theme.of(context).colorScheme.inversePrimary,
           title: Text(widget.title),
         ),
         body: Center(
           child: Column(
             mainAxisAlignment: MainAxisAlignment.center,
             children: <Widget>[
               const Text(
                 '你已经点击了按钮次数：',
               ),
               Text(
                 '$_counter',
                 style: Theme.of(context).textTheme.headlineMedium,
               ),
             ],
           ),
         ),
         floatingActionButton: FloatingActionButton(
           onPressed: () async {
             var dio = Dio(
                 BaseOptions(baseUrl: "https://jsonplaceholder.typicode.com/"));
             var res = dio.getCancellable("todos");
             print(RequestCancellable.tokens.length);
             var response = await res.response;
             print("response : ${response.data}");
             print(RequestCancellable.tokens.length);
   
             // 取消所有带有特定路径的请求
             RequestCancellable.cancellAll((token) => token.path == "todos");
           },
           tooltip: '增加',
           child: const Icon(Icons.add),
         ),
       );
     }
   }