fix: Add mounted checks and fix memory leaks across UI components

Address potential memory leaks and state-after-dispose issues:

- AppProvider: Add dispose method to clean up listeners and callbacks
- MapTab: Store and restore original location callback instead of nullifying
- MessagesTab: Use Timer instead of Future.delayed for highlight cleanup
- ConnectionDialog: Use named listener method for proper tab controller cleanup
- RoomLoginSheet: Add _isDisposed flag to handle async callback race conditions
- SettingsScreen: Clear location service callbacks in dispose
- Various screens: Add mounted checks before setState after async operations
  (contacts_tab, device_config, home_screen, map_management, packet_log,
   sar_template_management, sar_update_sheet, permission_request_dialog)

lib/providers/app_provider.dart

@@ -25,6 +25,8 @@ class AppProvider with ChangeNotifier {
   bool _isInitialized = false;
   bool get isInitialized => _isInitialized;
 
+  bool _isDisposed = false;
+
   bool _isSimpleMode = true;
   bool get isSimpleMode => _isSimpleMode;
 
@@ -683,4 +685,17 @@ class AppProvider with ChangeNotifier {
       'sarMarkers': messagesProvider.sarMarkerStats,
     };
   }
+
+  @override
+  void dispose() {
+    _isDisposed = true;
+    // Remove connection state listener
+    connectionProvider.removeListener(_handleConnectionStateChange);
+    // Clear location service callbacks
+    locationTrackingService.onPositionUpdate = null;
+    locationTrackingService.onBroadcastSent = null;
+    locationTrackingService.onError = null;
+    locationTrackingService.onTrackingStateChanged = null;
+    super.dispose();
+  }
 }

lib/screens/contacts_tab.dart

@@ -51,9 +51,11 @@ class _ContactsTabState extends State<ContactsTab> {
   }
 
   Future<void> _handleRefresh() async {
+    if (!mounted) return;
     final appProvider = context.read<AppProvider>();
     await appProvider.refresh();
     // Also refresh location
+    if (!mounted) return;
     await _getCurrentLocation();
   }
 

lib/screens/device_config_screen.dart

@@ -347,6 +347,8 @@ class _DeviceConfigScreenState extends State<DeviceConfigScreen> {
         ),
       );
 
+      if (!mounted) return;
+
       setState(() {
         _latController.text = position.latitude.toStringAsFixed(6);
         _lonController.text = position.longitude.toStringAsFixed(6);

lib/screens/home_screen.dart

@@ -279,6 +279,7 @@ class _HomeScreenState extends State<HomeScreen>
     final appProvider = context.watch<AppProvider>();
     if (_isMapEnabled != appProvider.isMapEnabled) {
       WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (!mounted) return;
         _updateTabController(appProvider.isMapEnabled);
       });
     }

lib/screens/map_management_screen.dart

@@ -409,6 +409,7 @@ class _MapManagementScreenState extends State<MapManagementScreen> {
         );
       }
     } catch (e) {
+      if (!mounted) return;
       setState(() => _isLoading = false);
       _showError(AppLocalizations.of(context)!.clearCacheFailed(e.toString()));
     }

lib/screens/map_tab.dart

@@ -78,6 +78,9 @@ class _MapTabState extends State<MapTab> with AutomaticKeepAliveClientMixin {
   // MBTiles layers
   List<MapLayer> _mbtilesLayers = [];
 
+  // Store original location callback to restore in dispose
+  void Function(Position)? _originalLocationCallback;
+
   // WMS layers (Slovenian)
   late final MapLayer _slovenianAerialLayer;
   late final MapLayer _dtk25Layer;
@@ -128,6 +131,7 @@ class _MapTabState extends State<MapTab> with AutomaticKeepAliveClientMixin {
 
     // Listen to map provider for navigation requests
     WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (!mounted) return; // Check if widget is still mounted
       final mapProvider = context.read<MapProvider>();
       mapProvider.addListener(_handleMapNavigation);
       // Load WMS overlay state
@@ -146,13 +150,13 @@ class _MapTabState extends State<MapTab> with AutomaticKeepAliveClientMixin {
   /// Note: LocationTrackingService is initialized and started by AppProvider
   /// This method only adds map-specific callbacks for rotation and UI updates
   void _setupLocationCallbacks() {
-    // Store the original callback from AppProvider
+    // Store the original callback from AppProvider to restore in dispose
-    final originalCallback = _locationService.onPositionUpdate;
+    _originalLocationCallback = _locationService.onPositionUpdate;
 
     // Add map-specific callback that chains with the original
     _locationService.onPositionUpdate = (position) {
       // Call original callback first (AppProvider's logging)
-      originalCallback?.call(position);
+      _originalLocationCallback?.call(position);
 
       // Then handle map-specific logic - early exit if not mounted or disposing
       if (!mounted || _isDisposing) {
@@ -437,8 +441,8 @@ class _MapTabState extends State<MapTab> with AutomaticKeepAliveClientMixin {
     mapProvider.removeListener(_handleMapNavigation);
 
     // DO NOT stop location tracking - it's managed by AppProvider
-    // Just clear the map-specific callback
+    // Restore the original callback instead of setting to null
-    _locationService.onPositionUpdate = null;
+    _locationService.onPositionUpdate = _originalLocationCallback;
     _mapController.dispose();
     _tileCache.dispose();
     super.dispose();

lib/screens/messages_tab.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:provider/provider.dart';
@@ -33,6 +34,7 @@ class _MessagesTabState extends State<MessagesTab> {
   int _characterCount = 0;
   static const int _maxCharacters = 160;
   String? _highlightedMessageId;
+  Timer? _highlightTimer; // Timer for clearing message highlight
 
   // Message destination state
   String _destinationType =
@@ -73,6 +75,7 @@ class _MessagesTabState extends State<MessagesTab> {
 
   @override
   void dispose() {
+    _highlightTimer?.cancel();
     _textController.dispose();
     _focusNode.dispose();
     _scrollController.dispose();
@@ -112,8 +115,9 @@ class _MessagesTabState extends State<MessagesTab> {
         _highlightedMessageId = messageId;
       });
 
-      // Clear highlight after 2 seconds
+      // Clear highlight after 2 seconds using a properly managed Timer
-      Future.delayed(const Duration(seconds: 2), () {
+      _highlightTimer?.cancel();
+      _highlightTimer = Timer(const Duration(seconds: 2), () {
         if (mounted) {
           setState(() {
             _highlightedMessageId = null;

lib/screens/packet_log_screen.dart

@@ -73,10 +73,12 @@ class _PacketLogScreenState extends State<PacketLogScreen> {
 
       // Save to temporary file
       final tempDir = await getTemporaryDirectory();
+      if (!context.mounted) return;
       final file = File('${tempDir.path}/ble_packets_${DateTime.now().millisecondsSinceEpoch}.csv');
       await file.writeAsString(buffer.toString());
 
       // Share the file
+      if (!context.mounted) return;
       await Share.shareXFiles(
         [XFile(file.path)],
         subject: 'MeshCore BLE Packet Logs',
@@ -118,10 +120,12 @@ class _PacketLogScreenState extends State<PacketLogScreen> {
 
       // Save to temporary file
       final tempDir = await getTemporaryDirectory();
+      if (!context.mounted) return;
       final file = File('${tempDir.path}/ble_packets_${DateTime.now().millisecondsSinceEpoch}.txt');
       await file.writeAsString(buffer.toString());
 
       // Share the file
+      if (!context.mounted) return;
       await Share.shareXFiles(
         [XFile(file.path)],
         subject: 'MeshCore BLE Packet Logs',
@@ -147,27 +151,31 @@ class _PacketLogScreenState extends State<PacketLogScreen> {
   }
 
   void _clearLogs(BuildContext context) {
+    final parentContext = context; // Store parent context for setState
     showDialog(
       context: context,
-      builder: (context) => AlertDialog(
+      builder: (dialogContext) => AlertDialog(
-        title: Text(AppLocalizations.of(context)!.clearAllData),
+        title: Text(AppLocalizations.of(dialogContext)!.clearAllData),
         content: const Text('Are you sure you want to clear all packet logs? This cannot be undone.'),
         actions: [
           TextButton(
-            onPressed: () => Navigator.pop(context),
+            onPressed: () => Navigator.pop(dialogContext),
-            child: Text(AppLocalizations.of(context)!.cancel),
+            child: Text(AppLocalizations.of(dialogContext)!.cancel),
           ),
           TextButton(
             onPressed: () {
               widget.bleService.clearPacketLogs();
-              Navigator.pop(context);
+              Navigator.pop(dialogContext);
+              if (!mounted) return;
               setState(() {});
-              ScaffoldMessenger.of(context).showSnackBar(
+              if (parentContext.mounted) {
-                const SnackBar(content: Text('Packet logs cleared')),
+                ScaffoldMessenger.of(parentContext).showSnackBar(
-              );
+                  const SnackBar(content: Text('Packet logs cleared')),
+                );
+              }
             },
             style: TextButton.styleFrom(foregroundColor: Colors.red),
-            child: Text(AppLocalizations.of(context)!.clear),
+            child: Text(AppLocalizations.of(dialogContext)!.clear),
           ),
         ],
       ),
@@ -381,6 +389,7 @@ class _PacketLogScreenState extends State<PacketLogScreen> {
                       // Auto-scroll to bottom
                       if (_autoScroll && index == logs.length - 1) {
                         WidgetsBinding.instance.addPostFrameCallback((_) {
+                          if (!mounted) return;
                           if (_scrollController.hasClients) {
                             _scrollController.animateTo(
                               _scrollController.position.maxScrollExtent,

lib/screens/sar_template_management_screen.dart

@@ -24,6 +24,7 @@ class _SarTemplateManagementScreenState extends State<SarTemplateManagementScree
 
   Future<void> _initializeService() async {
     if (!_templateService.isInitialized) {
+      if (!mounted) return;
       setState(() => _isLoading = true);
       await _templateService.initialize();
       if (mounted) {
@@ -111,6 +112,7 @@ class _SarTemplateManagementScreenState extends State<SarTemplateManagementScree
   }
 
   Future<void> _importFromClipboard() async {
+    if (!mounted) return;
     setState(() => _isLoading = true);
 
     try {

lib/screens/settings_screen.dart

@@ -57,6 +57,15 @@ class _SettingsScreenState extends State<SettingsScreen> {
     _loadRxTxPreference();
   }
 
+  @override
+  void dispose() {
+    // Clear location service callbacks to prevent memory leaks
+    _locationService.onError = null;
+    _locationService.onBroadcastSent = null;
+    _locationService.onTrackingStateChanged = null;
+    super.dispose();
+  }
+
   Future<void> _loadPackageInfo() async {
     final info = await PackageInfo.fromPlatform();
     if (mounted) {

lib/widgets/connection_dialog.dart

@@ -22,6 +22,26 @@ class _ConnectionDialogState extends State<ConnectionDialog>
   int _totalToScan = 0;
   String? _connectingToServerUrl; // Track which server is being connected to
 
+  // Named listener method for proper cleanup
+  void _onTabChanged() {
+    if (_tabController.index == 1) {
+      // Switched to network tab
+      if (_networkScanner.hasCachedResults && _discoveredServers.isEmpty) {
+        // Load cached results
+        setState(() {
+          _discoveredServers.addAll(_networkScanner.cachedServers);
+        });
+        debugPrint(
+          '📦 [NetworkScanner] Loaded ${_discoveredServers.length} servers from cache',
+        );
+      } else if (!_networkScanner.isScanning &&
+          !_networkScanner.hasCachedResults) {
+        // No cache, start initial scan
+        _startNetworkScan();
+      }
+    }
+  }
+
   @override
   void initState() {
     super.initState();
@@ -55,25 +75,8 @@ class _ConnectionDialogState extends State<ConnectionDialog>
       }
     };
 
-    // Listen to tab changes
+    // Listen to tab changes using named method for proper cleanup
-    _tabController.addListener(() {
+    _tabController.addListener(_onTabChanged);
-      if (_tabController.index == 1) {
-        // Switched to network tab
-        if (_networkScanner.hasCachedResults && _discoveredServers.isEmpty) {
-          // Load cached results
-          setState(() {
-            _discoveredServers.addAll(_networkScanner.cachedServers);
-          });
-          debugPrint(
-            '📦 [NetworkScanner] Loaded ${_discoveredServers.length} servers from cache',
-          );
-        } else if (!_networkScanner.isScanning &&
-            !_networkScanner.hasCachedResults) {
-          // No cache, start initial scan
-          _startNetworkScan();
-        }
-      }
-    });
   }
 
   @override
@@ -84,6 +87,8 @@ class _ConnectionDialogState extends State<ConnectionDialog>
     );
     connectionProvider.stopScan();
     _networkScanner.stopScan();
+    // Remove listener before disposing to prevent memory leaks
+    _tabController.removeListener(_onTabChanged);
     _tabController.dispose();
     super.dispose();
   }

lib/widgets/contacts/direct_message_sheet.dart

@@ -41,6 +41,7 @@ class _DirectMessageSheetState extends State<DirectMessageSheet> {
   }
 
   void _updateCharacterCount() {
+    if (!mounted) return;
     setState(() {
       _characterCount = _textController.text.length;
     });

lib/widgets/contacts/room_login_sheet.dart

@@ -21,6 +21,7 @@ class _RoomLoginSheetState extends State<RoomLoginSheet> {
   final FocusNode _focusNode = FocusNode();
   bool _isLoggingIn = false;
   bool _obscurePassword = true;
+  bool _isDisposed = false; // Track disposal state for async callbacks
 
   @override
   void initState() {
@@ -30,6 +31,7 @@ class _RoomLoginSheetState extends State<RoomLoginSheet> {
 
   @override
   void dispose() {
+    _isDisposed = true;
     _passwordController.dispose();
     _focusNode.dispose();
     super.dispose();
@@ -245,15 +247,15 @@ class _RoomLoginSheetState extends State<RoomLoginSheet> {
         '   Messages will be fetched when onMessageWaiting callback is triggered',
       );
 
-      if (mounted) {
+      // Check both _isDisposed flag and mounted to handle race conditions
-        ScaffoldMessenger.of(context).showSnackBar(
+      if (_isDisposed || !mounted) return;
-          SnackBar(
+      ScaffoldMessenger.of(context).showSnackBar(
-            content: Text(AppLocalizations.of(context)!.loggedInSuccessfully),
+        SnackBar(
-            backgroundColor: Theme.of(context).colorScheme.primary,
+          content: Text(AppLocalizations.of(context)!.loggedInSuccessfully),
-            duration: const Duration(seconds: 3),
+          backgroundColor: Theme.of(context).colorScheme.primary,
-          ),
+          duration: const Duration(seconds: 3),
-        );
+        ),
-      }
+      );
     };
 
     connectionProvider.onLoginFail = (publicKeyPrefix) {
@@ -263,15 +265,15 @@ class _RoomLoginSheetState extends State<RoomLoginSheet> {
 
       debugPrint('❌ [RoomLogin] Login failed - incorrect password');
 
-      if (mounted) {
+      // Check both _isDisposed flag and mounted to handle race conditions
-        ScaffoldMessenger.of(context).showSnackBar(
+      if (_isDisposed || !mounted) return;
-          SnackBar(
+      ScaffoldMessenger.of(context).showSnackBar(
-            content: Text(AppLocalizations.of(context)!.loginFailed),
+        SnackBar(
-            backgroundColor: Theme.of(context).colorScheme.error,
+          content: Text(AppLocalizations.of(context)!.loginFailed),
-            duration: const Duration(seconds: 3),
+          backgroundColor: Theme.of(context).colorScheme.error,
-          ),
+          duration: const Duration(seconds: 3),
-        );
+        ),
-      }
+      );
     };
 
     try {

lib/widgets/messages/sar_update_sheet.dart

@@ -231,6 +231,7 @@ class _SarUpdateSheetState extends State<SarUpdateSheet> {
     try {
       // Check if location services are enabled
       bool serviceEnabled = await Geolocator.isLocationServiceEnabled();
+      if (!mounted) return;
       if (!serviceEnabled) {
         setState(() {
           _locationError = 'Location services are disabled';
@@ -241,8 +242,10 @@ class _SarUpdateSheetState extends State<SarUpdateSheet> {
 
       // Check permissions
       LocationPermission permission = await Geolocator.checkPermission();
+      if (!mounted) return;
       if (permission == LocationPermission.denied) {
         permission = await Geolocator.requestPermission();
+        if (!mounted) return;
         if (permission == LocationPermission.denied) {
           setState(() {
             _locationError = 'Location permission denied';

lib/widgets/permission_request_dialog.dart

@@ -38,6 +38,7 @@ class _PermissionRequestDialogState extends State<PermissionRequestDialog> {
     try {
       // Check if location service is enabled
       final serviceEnabled = await Geolocator.isLocationServiceEnabled();
+      if (!mounted) return;
       if (!serviceEnabled) {
         setState(() {
           _errorMessage = 'Location services are disabled. Please enable location services in your device settings.';
@@ -48,10 +49,12 @@ class _PermissionRequestDialogState extends State<PermissionRequestDialog> {
 
       // Check current permission
       LocationPermission permission = await Geolocator.checkPermission();
+      if (!mounted) return;
 
       if (permission == LocationPermission.denied) {
         // Request permission
         permission = await Geolocator.requestPermission();
+        if (!mounted) return;
       }
 
       if (permission == LocationPermission.denied) {
@@ -78,11 +81,10 @@ class _PermissionRequestDialogState extends State<PermissionRequestDialog> {
       });
 
       // Close dialog and notify parent
-      if (mounted) {
+      Navigator.of(context).pop();
-        Navigator.of(context).pop();
+      widget.onPermissionsGranted();
-        widget.onPermissionsGranted();
-      }
     } catch (e) {
+      if (!mounted) return;
       setState(() {
         _errorMessage = 'Error requesting permissions: $e';
         _isRequesting = false;