open ai service

2026-02-08 12:05:05 +06:00
parent d7722ad81d
commit 3209827e92
29 changed files with 2175 additions and 0 deletions
--- a/books_flutter/lib/widgets/bottom_nav_shell.dart
+++ b/books_flutter/lib/widgets/bottom_nav_shell.dart
@@ -0,0 +1,99 @@
+import 'package:flutter/material.dart';
+import 'bottom_nav.dart';
+import '../screens/library_screen.dart';
+import '../screens/categories_screen.dart';
+
+/// Shell widget with bottom navigation and nested navigators for each tab.
+/// Uses IndexedStack to preserve navigation state when switching tabs.
+class BottomNavShell extends StatefulWidget {
+  const BottomNavShell({super.key});
+
+  @override
+  State<BottomNavShell> createState() => _BottomNavShellState();
+}
+
+class _BottomNavShellState extends State<BottomNavShell> {
+  int _currentIndex = 0;
+
+  // Each tab gets its own navigator key to maintain independent navigation stacks
+  final _navigatorKeys = List.generate(4, (_) => GlobalKey<NavigatorState>());
+
+  @override
+  Widget build(BuildContext context) {
+    return PopScope(
+      canPop: false,
+      onPopInvokedWithResult: (didPop, result) async {
+        if (didPop) return;
+        final shouldPop = await _onWillPop();
+        if (shouldPop && context.mounted) {
+          Navigator.of(context).pop();
+        }
+      },
+      child: Scaffold(
+        body: IndexedStack(
+          index: _currentIndex,
+          children: [
+            _buildNavigator(0, (_) => const LibraryScreen()),
+            _buildNavigator(1, (_) => const CategoriesScreen()),
+            _buildNavigator(2, (_) => _buildPlaceholder('Избранное')),
+            _buildNavigator(3, (_) => _buildPlaceholder('Настройки')),
+          ],
+        ),
+        bottomNavigationBar: BottomNav(
+          currentIndex: _currentIndex,
+          onTap: _onTabTapped,
+        ),
+      ),
+    );
+  }
+
+  /// Builds a nested navigator for a tab
+  Widget _buildNavigator(int index, WidgetBuilder builder) {
+    return Navigator(
+      key: _navigatorKeys[index],
+      onGenerateRoute: (settings) {
+        return MaterialPageRoute(builder: builder, settings: settings);
+      },
+    );
+  }
+
+  /// Placeholder screen for tabs not yet implemented
+  Widget _buildPlaceholder(String title) {
+    return Scaffold(
+      appBar: AppBar(title: Text(title), automaticallyImplyLeading: false),
+      body: Center(
+        child: Text(title, style: Theme.of(context).textTheme.headlineMedium),
+      ),
+    );
+  }
+
+  /// Handle tab selection
+  void _onTabTapped(int index) {
+    if (_currentIndex == index) {
+      // If tapping the current tab, pop to root of that tab's navigator
+      final navigator = _navigatorKeys[index].currentState;
+      if (navigator != null && navigator.canPop()) {
+        navigator.popUntil((route) => route.isFirst);
+      }
+    } else {
+      // Switch to the selected tab
+      setState(() {
+        _currentIndex = index;
+      });
+    }
+  }
+
+  /// Handle system back button
+  Future<bool> _onWillPop() async {
+    final navigator = _navigatorKeys[_currentIndex].currentState;
+
+    // If the current tab's navigator can pop, pop it
+    if (navigator != null && navigator.canPop()) {
+      navigator.pop();
+      return false; // Don't exit app
+    }
+
+    // If on root of current tab, allow app to exit
+    return true;
+  }
+}