flutter webscoket连接，聊天_dart web_socket_channel

import 'dart:async';
import 'dart:convert';
import 'package:web_socket_channel/web_socket_channel.dart';
import '../pages/play/live_id.dart';
class WebSocketManager {
  static final WebSocketManager _instance = WebSocketManager._internal();
 
  WebSocketManager._internal();
 
  static WebSocketManager getInstance() {
    return _instance;
  }
 
  WebSocketChannel? _channel;
  bool _isConnected = false;
  int _heartbeatInterval = 30000;
  Timer? _heartbeatTimer;
  Future<void> connect() async {
    print('_channel${_channel}');
    if (_channel != null) {
      return; // 连接已建立，直接返回
    }
 
    final url= 'ws://你自己的url';
 
    try {
      _channel = await WebSocketChannel.connect(Uri.parse(url));
      print('_channel_channel_channel_channel${_channel}');
      _channel?.stream.listen((data) {
        _onMessage(data);
      }, onError: (error) {
        _onConnectionFailed(error);
      }, onDone: () {
        _onConnectionClosed();
      });
 
      _startHeartbeat();
 
      _isConnected = true;
      _onConnectionSuccess();
    } catch (e) {
      _onConnectionFailed(e);
    }
  }
 
  void sendJoinGroupChat(String groupId) {
    if (_isConnected) {
      Map<String, dynamic> joinMessage = {
        "type": "joinGroupChat",
        "groupId": groupId,
      };
      var json = jsonEncode(joinMessage);
      _channel?.sink.add(json);
    }
  }
 
  void exitGroupChat(String groupId) {
    if (_isConnected) {
      Map<String, dynamic> joinMessage = {
        "type": "exitGroupChat",
        "groupId": groupId,
      };
      var json = jsonEncode(joinMessage);
      _channel?.sink.add(json);
    }
  }
 
  void sendGroupMessage(String groupId, String contentText) {
    print('_isConnected${_isConnected}');
 
    if (_isConnected) {
      Map<String, dynamic> message = {
        "type": "sendGroupMsg",
        "groupId": groupId,
        "contentText": contentText,
      };
      var json = jsonEncode(message);
      _channel?.sink.add(json);
    }
  }
 
  void disconnect() {
    _channel?.sink.close();
    _heartbeatTimer?.cancel();
    _isConnected = false;
  }
 
  void _onConnectionSuccess() {
    homeG.webscoket = true;
    print("连接成功");
  }
 
  void _onMessage(dynamic data) {
    if (_isConnected) {
      Map<String, dynamic> remessage = {
        "type": "receiveGroupMsg",
      };
      // _channel?.sink.add(remessage.toString());
      var json = jsonEncode(remessage);
      _channel?.sink.add(json);
    }
    print("收到消息：$data");
    // 在这里处理接收到的消息
  }
 
  void _onConnectionFailed(dynamic error) {
    print("连接失败：$error");
    // 重连
    Future.delayed(Duration(seconds: 3), () {
      // connect(_channel?.url?.origin ?? "", "staffid");
      connect();
    });
  }
 
  void _onConnectionClosed() {
    homeG.webscoket = false;
    print("连接关闭");
  }
 
  void _startHeartbeat() {
    _heartbeatTimer =
        Timer.periodic(Duration(milliseconds: _heartbeatInterval), (timer) {
      sendHeartbeat();
    });
  }
 
  void sendHeartbeat() {
    if (_isConnected) {
      Map<String, dynamic> heartbeatMessage = {
        "type": "heart",
      };
      // _channel?.sink.add(heartbeatMessage.toString());
      var json = jsonEncode(heartbeatMessage);
      _channel?.sink.add(json);
    }
  }
}

需要用jsonEncode编码一下成json类型传给后端