如何在颤动中连接到 TCP 套接字（不是 Web 套接字）？

Posted 2023-05-07

【中文标题】如何在颤动中连接到 TCP 套接字（不是 Web 套接字）？

【英文标题】：How can i connect to TCP socket (not web socket) in flutter?

【发布时间】：2021-11-26 13:38:44

【问题描述】：

import 'dart:typed_data';
import 'package:flutter/foundation.dart';
import 'dart:io';
import 'package:flutter/material.dart';

void main() async 

  Socket sock = await Socket.connect('192.168.1.150', 2662);
  print('Connected to: $sock.remoteAddress.address:$sock.remotePort');
  runApp(MyApp(sock));
  sock.listen(
       
        (Uint8List data) 
      final serverResponse = String.fromCharCodes(data);
      print('Server: $serverResponse');
    ,
    
    onError: (error) 
      print(error);
      sock.destroy();
    ,

    onDone: () 
      print('Server left.');
      sock.destroy();
    ,
  );


class MyApp extends StatelessWidget 
  Socket socket;

  MyApp(Socket s) 
    this.socket = s;
    s.listen(

          (Uint8List data) 
        final serverResponse = String.fromCharCodes(data);
        print('Server: $serverResponse');
      ,

      // handle errors
      onError: (error) 
        print(error);
        s.destroy();
      ,

      onDone: () 
        print('Server left.');
        s.destroy();
      ,
    );
  

  @override
  Widget build(BuildContext context) 
    final title = 'Example';
    return MaterialApp(
      title: title,
      home: MyHomePage(
        title: title,
        channel: socket,
      ),
    );
  


class MyHomePage extends StatefulWidget 
  final String title;
  final Socket channel;

  MyHomePage(Key key, @required this.title, @required this.channel)
      : super(key: key);

  @override
  _MyHomePageState createState() => _MyHomePageState();


class _MyHomePageState extends State<MyHomePage> 
  TextEditingController _controller = TextEditingController();

  @override
  Widget build(BuildContext context) 

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Padding(
        padding: const EdgeInsets.all(20.0),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            Form(
              child: TextFormField(
                controller: _controller,
                decoration: InputDecoration(labelText: 'Send a message'),
              ),
            ),
            StreamBuilder(
              stream: widget.channel,
              builder: (context, snapshot) 
                return Padding(
                  padding: const EdgeInsets.symmetric(vertical: 24.0),
                  child: Text(snapshot.hasData
                      ? '$String.fromCharCodes(snapshot.data)'
                      : ''),
                );
              ,
            )
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _sendMessage,
        tooltip: 'Send message',
        child: Icon(Icons.send),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  

  void _sendMessage() 
    if (_controller.text.isNotEmpty) 
      widget.channel.write(_controller.text);
    
  

  @override
  void dispose() 
    widget.channel.close();
    super.dispose();
  

---

当我在模拟器上运行代码时，我得到这个错误： " 调试服务监听 ws://127.0.0.1:59871/2EzZsU03nwc=/ws 正在将文件同步到 IA 模拟器上的设备 AOSP..."

与

“E/flutter (24126): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] 未处理异常: SocketException: OS Error: Connection timed out, errno = 110, address = 192.168.1.131, port = 51170"

我该如何解决这个问题？

谢谢。

【参考方案1】：

这是连接到服务器上 TCP 套接字的最简单的 Dart 程序。它发送“你好”，等待 5 秒等待任何回复，然后关闭套接字。您可以将其与您自己的服务器一起使用，或者像 this one. 这样的简单回显服务器

import 'dart:io';
import 'dart:convert';
import 'dart:async';

main() async 
  Socket socket = await Socket.connect('192.168.1.99', 1024);
  print('connected');

  // listen to the received data event stream
  socket.listen((List<int> event) 
    print(utf8.decode(event));
  );

  // send hello
  socket.add(utf8.encode('hello'));

  // wait 5 seconds
  await Future.delayed(Duration(seconds: 5));

  // .. and close the socket
  socket.close();

【讨论】：

嗨，我按照你说的做了，但我又遇到了同样的错误。 E/flutter (25374): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] 未处理异常：SocketException: OS 错误：连接超时，errno = 110，地址 = 192.168.1.150，端口 = 58384跨度>

你可以尝试清理并再次运行吗？

我打开了终端。我做了flutter -clear，然后flutter-run它构建了它，但不幸的是它给出了同样的错误。

嗨，G H Prakash，如何在使用 Flutter TCP 套接字按下按钮时发送消息？谢谢...

我在 python 中有一个接收器，绑定 socket.bind("tcp://127.0.0.1:5556") 我使用 socket = await Socket.connect('127.0.0.1', 5556); 与颤振连接，但是当我使用 socket.add(utf8.encode('hello')); 发送消息时，其他程序没有收到任何内容