ADD ALOT OF POLISHING AND UPDATES...

walkguide-mobile/walkguide_app/lib/features/navigation_mode/navigation_mode_screen.dart

@@ -9,6 +9,7 @@ import 'dart:async';
 import 'package:dio/dio.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_map/flutter_map.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:geolocator/geolocator.dart';
 import 'package:latlong2/latlong.dart';
 
@@ -38,12 +39,14 @@ class _Step {
       required this.point});
 }
 
-// ─── BLoC-lite state (plain ChangeNotifier to avoid heavy BLoC boilerplate
-//      while staying consistent with the rest of screens.dart approach) ─────
+// Navigation state is kept in a lightweight Cubit so the app uses one
+// state-management family consistently.
 
 enum _NavPhase { idle, locating, routing, navigating, error }
 
-class _NavState extends ChangeNotifier {
+class _NavState extends Cubit<int> {
+  _NavState() : super(0);
+
   _NavPhase phase = _NavPhase.idle;
   String statusText = 'Ketuk tombol lokasi atau cari tujuan.';
   LatLng? currentPosition;
@@ -59,9 +62,11 @@ class _NavState extends ChangeNotifier {
   void _set(_NavPhase p, String status) {
     phase = p;
     statusText = status;
-    notifyListeners();
+    _notify();
   }
 
+  void _notify() => emit(state + 1);
+
   // ── locate ──────────────────────────────────────────────────────────────
   Future<bool> locate() async {
     _set(_NavPhase.locating, 'Mencari lokasi GPS…');
@@ -85,7 +90,8 @@ class _NavState extends ChangeNotifier {
       _set(_NavPhase.error, 'GPS timeout. Pastikan GPS aktif.');
       return false;
     } catch (e) {
-      _set(_NavPhase.error, 'GPS error: $e');
+      _set(_NavPhase.error,
+          'Lokasi belum bisa dibaca. Pastikan GPS dan izin lokasi aktif.');
       return false;
     }
   }
@@ -211,10 +217,11 @@ class _NavState extends ChangeNotifier {
 
       _set(_NavPhase.navigating,
           steps.isNotEmpty ? steps[0].instruction : 'Ikuti rute biru.');
-      notifyListeners();
+      _notify();
       _startTracking();
     } catch (e) {
-      _set(_NavPhase.error, 'Gagal mendapat rute: $e');
+      _set(_NavPhase.error,
+          'Gagal mendapat rute. Periksa koneksi lalu coba lagi.');
     }
   }
 
@@ -283,7 +290,7 @@ class _NavState extends ChangeNotifier {
       currentPosition = LatLng(pos.latitude, pos.longitude);
       _reportToBackend(pos);
       _updateStep();
-      notifyListeners();
+      _notify();
     });
   }
 
@@ -302,7 +309,7 @@ class _NavState extends ChangeNotifier {
         final next = steps[currentStepIndex];
         statusText = next.instruction;
         sl<TtsService>().speak(next.instruction);
-        notifyListeners();
+        _notify();
       }
     }
   }
@@ -318,9 +325,9 @@ class _NavState extends ChangeNotifier {
   }
 
   @override
-  void dispose() {
+  Future<void> close() {
     _posStream?.cancel();
-    super.dispose();
+    return super.close();
   }
 }
 
@@ -339,6 +346,7 @@ class _NavigationModeScreenState extends State<NavigationModeScreen> {
   final _searchCtrl = TextEditingController();
   final _searchFocus = FocusNode();
 
+  StreamSubscription<int>? _navSubscription;
   List<_Place> _suggestions = const [];
   bool _searchLoading = false;
   bool _showSuggestions = false;
@@ -348,7 +356,7 @@ class _NavigationModeScreenState extends State<NavigationModeScreen> {
   @override
   void initState() {
     super.initState();
-    _navState.addListener(_onStateChange);
+    _navSubscription = _navState.stream.listen((_) => _onStateChange());
     WidgetsBinding.instance.addPostFrameCallback((_) => _init());
   }
 
@@ -433,8 +441,8 @@ class _NavigationModeScreenState extends State<NavigationModeScreen> {
   @override
   void dispose() {
     _debounce?.cancel();
-    _navState.removeListener(_onStateChange);
-    _navState.dispose();
+    _navSubscription?.cancel();
+    _navState.close();
     _searchCtrl.dispose();
     _searchFocus.dispose();
     super.dispose();