implement refreshing chat screen(This foundation really kills me)

lib/models/websocket_model.dart

@@ -30,7 +30,7 @@ class WebSocketManager extends ChangeNotifier {
   Timer? heartBeatTimer;
   Timer? serverTimer;
   Timer? reconnectTimer;
-  int reconnectCount = 10;
+  int reconnectCount = 5;
   int reconnectTimes = 0;
   Duration heartBeatTimeout = const Duration(seconds: 4);
   Duration reconnectTimeout = const Duration(seconds: 3);
@@ -38,6 +38,10 @@ class WebSocketManager extends ChangeNotifier {
   void connect(String userId, bool isReconnect) {
     id = userId;
     wsUrl = Uri.parse('ws://10.0.2.2:8000/ws/$id?is_reconnect=$isReconnect');
+    if (isReconnect) {
+      socketStatus = SocketStatus.reconnecting;
+      notifyListeners();
+    }
     // This doesn't blcok the programe whethe it connect the server or not
     // So heartBeat will be executre straightly
     channel = WebSocketChannel.connect(wsUrl);
@@ -97,7 +101,7 @@ class WebSocketManager extends ChangeNotifier {
   // for example server is restarting
   void onDone() {
     print('websocket disconnected <$channel>');
-
+    print('22222222222222222222');
     if (socketStatus == SocketStatus.closed) {
       // Client close the connection
       return;
@@ -112,6 +116,11 @@ class WebSocketManager extends ChangeNotifier {
     }
     if (reconnectTimes >= reconnectCount) {
       socketStatus = SocketStatus.error;
+      reconnectTimes = 0;
+    } else {
+      socketStatus = SocketStatus.reconnecting;
+      print('3333333333333333333');
+      notifyListeners();
     }
   }
 
@@ -121,12 +130,12 @@ class WebSocketManager extends ChangeNotifier {
     // print(st);
     if (reconnectTimes >= reconnectCount) {
       socketStatus = SocketStatus.error;
+      notifyListeners();
+      channel.sink.close();
       if (heartBeatTimer != null) {
         heartBeatTimer!.cancel();
         heartBeatTimer = null;
       }
-      channel.sink.close();
-      notifyListeners();
     } else {
       print('${reconnectTimes}th reconnection');
       reconnect();

lib/screens/chat/chat_screen.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 
 import 'package:cached_network_image/cached_network_image.dart';
@@ -150,11 +152,30 @@ class _ChatScreenState extends State<ChatScreen> with GetItStateMixin {
                 Expanded(
                   child: RefreshIndicator(
                     onRefresh: () async {
-                      String userId = getIt.get<UserAccount>().id;
+                      if (socketStatus == SocketStatus.reconnecting) {
-                      if (socketStatus == SocketStatus.error) {
+                        return;
-                        getIt.get<WebSocketManager>().connect(userId, false);
                       }
+
+                      String userId = getIt.get<UserAccount>().id;
+
+                      if (socketStatus != SocketStatus.connected) {
+                        getIt.get<WebSocketManager>().connect(userId, true);
+
+                        await Future.doWhile(() async {
+                          SocketStatus socketStatus =
+                              get<WebSocketManager>().socketStatus;
+                          await Future.delayed(
+                            const Duration(milliseconds: 500),
+                          );
+                          return socketStatus == SocketStatus.reconnecting;
+                        });
+
+                        SocketStatus socketStatus =
+                            get<WebSocketManager>().socketStatus;
+                        if (socketStatus == SocketStatus.connected) {
                           await _getUnreceivedMsg(userId);
+                        }
+                      }
                     },
                     child: ValueListenableBuilder(
                       valueListenable:
@@ -171,15 +192,24 @@ class _ChatScreenState extends State<ChatScreen> with GetItStateMixin {
                         );
 
                         if (openedChat.isEmpty) {
-                          return const Center(
+                          return LayoutBuilder(builder: (context, constrains) {
+                            return ListView(
+                              itemExtent: constrains.maxHeight / 3,
+                              children: const [
+                                SizedBox(),
+                                Center(
                                   child: Text(
                                     '没有最新消息',
                                     style: TextStyle(
                                       fontSize: 18,
-                                letterSpacing: 5.0,
+                                      letterSpacing: 4.0,
                                     ),
                                   ),
+                                ),
+                                SizedBox(),
+                              ],
                             );
+                          });
                         } else {
                           return ListView.builder(
                             physics: const BouncingScrollPhysics(