fix: wait for WidgetsFlutterBinding to initialize

lib/main.dart

@@ -1,9 +1,11 @@
 import "package:flutter/services.dart";
 import 'routes.dart';
+import 'package:flutter/widgets.dart';
 // import 'package:flutter/rendering.dart';
 
 void main() {
   // debugPaintSizeEnabled = true;
+  WidgetsFlutterBinding.ensureInitialized();
   SystemChrome.setSystemUIOverlayStyle(SystemUiOverlayStyle.light);
   Routes();
 }

lib/src/services/connection_status.dart

@@ -0,0 +1,67 @@
+import 'dart:io';
+import 'dart:async';
+import 'package:connectivity/connectivity.dart';
+
+/// Singleton class to get a stream of the current network connection status.
+class ConnectionStatus {
+  static final ConnectionStatus _singleton = ConnectionStatus._internal();
+  static final Connectivity _connectivity = Connectivity();
+
+  StreamController<bool> _connectionChangeController;
+
+  bool _hasConnection = false;
+
+  /// Stream of current connection status. Only updates when there is a change in connection.
+  Stream<bool> get connectionChange => _connectionChangeController.stream;
+
+  /// Private internal constructor for the Singleton
+  ConnectionStatus._internal() {
+    // Only call the init function when there is a subscriber to the stream
+    _connectionChangeController =
+        StreamController<bool>.broadcast(onListen: _init);
+  }
+
+  _init() async {
+    _checkConnection();
+
+    // Recheck the connection when device connectivity changes (e.g. WiFi enabled/disabled)
+    _connectivity.onConnectivityChanged.listen((result) => _checkConnection());
+
+    // Set a timer to check the connection periodically
+    Timer.periodic(Duration(seconds: 20), (Timer t) {
+      _checkConnection();
+    });
+  }
+
+  /// Checks the current connection status and updates _connectionChangeController if required.
+  Future<bool> _checkConnection() async {
+    bool prevConnection = _hasConnection;
+
+    try {
+      // Verify connection by resolving example.com
+      final result = await InternetAddress.lookup('example.com');
+      if (result.isNotEmpty && result[0].rawAddress.isNotEmpty) {
+        _hasConnection = true;
+      } else {
+        _hasConnection = false;
+      }
+    } on SocketException {
+      _hasConnection = false;
+    }
+
+    // Update the stream controller if there is a change in connection
+    if (prevConnection != _hasConnection) {
+      _connectionChangeController.add(_hasConnection);
+    }
+
+    return _hasConnection;
+  }
+
+  void dispose() {
+    _connectionChangeController.close();
+  }
+
+  factory ConnectionStatus() {
+    return _singleton;
+  }
+}

lib/src/ui/home.dart

@@ -1,4 +1,5 @@
 import "package:flutter/material.dart";
+import 'package:frontend_flutter/src/services/connection_status.dart';
 import 'dart:ui' as ui;
 
 import "../services/heartbeat_manager.dart";
@@ -35,6 +36,10 @@ class _HomeState extends State<Home> with SingleTickerProviderStateMixin {
   // Current conversaton
   String currentConversationId = "";
 
+  // Online status
+  ConnectionStatus connectionStatus = ConnectionStatus();
+  bool isOnline = true;
+
   @override
   initState() {
     super.initState();
@@ -48,6 +53,13 @@ class _HomeState extends State<Home> with SingleTickerProviderStateMixin {
 
     messageChannel.bus.listen(
         (Map<String, String> data) async => await _processMessage(data));
+
+    connectionStatus.connectionChange.listen((bool online) {
+      // TODO: implement some timer to remove the message after 3 seconds
+      setState(() {
+        isOnline = online;
+      });
+    });
   }
 
   @override
@@ -124,7 +136,12 @@ class _HomeState extends State<Home> with SingleTickerProviderStateMixin {
                     : Icon(data, color: Colors.grey, size: 20),
                 title: Container(),
               );
-            }).toList())
+            }).toList()),
+        Container(
+            width: MediaQuery.of(context).size.width,
+            alignment: Alignment(0.0, 0.0),
+            color: isOnline ? Colors.green : Colors.red,
+            child: Text(isOnline ? 'Online' : 'Offline')),
       ]),
     );
   }

pubspec.yaml

@@ -25,6 +25,7 @@ dependencies:
   flutter_slidable: ^0.5.3
   image_jpeg: ^1.1.1
   permission_handler: ^4.0.0
+  connectivity: ^0.4.6+1
 
 
 dev_dependencies: