update

lib/app/router.dart

@@ -0,0 +1,79 @@
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import '../features/dashboard/screen.dart';
+import '../features/add_transaction/screen.dart';
+import '../features/categories/screen.dart';
+
+final _shellKey = GlobalKey<NavigatorState>();
+
+final appRouter = GoRouter(
+  initialLocation: '/dashboard',
+  routes: [
+    ShellRoute(
+      navigatorKey: _shellKey,
+      builder: (context, state, child) => AppShell(child: child),
+      routes: [
+        GoRoute(
+          path: '/dashboard',
+          pageBuilder: (context, state) => const NoTransitionPage(
+            child: DashboardScreen(),
+          ),
+        ),
+        GoRoute(
+          path: '/categories',
+          pageBuilder: (context, state) => const NoTransitionPage(
+            child: CategoriesScreen(),
+          ),
+        ),
+      ],
+    ),
+    GoRoute(
+      path: '/add',
+      builder: (context, state) => const AddTransactionScreen(),
+    ),
+  ],
+);
+
+class AppShell extends StatelessWidget {
+  final Widget child;
+  const AppShell({super.key, required this.child});
+
+  int _locationToIndex(BuildContext context) {
+    final location = GoRouterState.of(context).uri.toString();
+    if (location.startsWith('/categories')) return 1;
+    return 0;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final idx = _locationToIndex(context);
+    return Scaffold(
+      body: child,
+      floatingActionButton: FloatingActionButton(
+        onPressed: () => context.push('/add'),
+        backgroundColor: const Color(0xFF7C6DED),
+        child: const Icon(Icons.add, color: Colors.white),
+      ),
+      floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
+      bottomNavigationBar: NavigationBar(
+        selectedIndex: idx,
+        onDestinationSelected: (i) {
+          if (i == 0) context.go('/dashboard');
+          if (i == 1) context.go('/categories');
+        },
+        destinations: const [
+          NavigationDestination(
+            icon: Icon(Icons.dashboard_outlined),
+            selectedIcon: Icon(Icons.dashboard_rounded),
+            label: 'Dashboard',
+          ),
+          NavigationDestination(
+            icon: Icon(Icons.pie_chart_outline_rounded),
+            selectedIcon: Icon(Icons.pie_chart_rounded),
+            label: 'Categories',
+          ),
+        ],
+      ),
+    );
+  }
+}