feat:增加底部标题栏

lib/layout/menu.dart

@@ -20,3 +20,8 @@ final List<PageInfo> pages = [
 ];
 
 final List<Widget> pageWidgets = pages.map((item) => item.page).toList();
+
+final List<BottomNavigationBarItem> bottomNavItems =
+    pages.map((page) {
+      return BottomNavigationBarItem(icon: Icon(page.icon), label: page.title);
+    }).toList();

lib/layout/nav_bar.dart

@@ -0,0 +1,22 @@
+import 'package:flutter/material.dart';
+
+import 'menu.dart';
+
+Widget buildBottomNavigationBar({
+  required BuildContext context,
+  required int index,
+  required Function(int) onTap,
+}) {
+  return BottomNavigationBar(
+    currentIndex: index,
+    onTap: onTap,
+    items: bottomNavItems,
+    type: BottomNavigationBarType.fixed,
+    selectedItemColor: Theme.of(context).colorScheme.primary,
+    unselectedItemColor: Colors.grey,
+    showSelectedLabels: true,
+    showUnselectedLabels: true,
+    backgroundColor: Colors.white,
+    elevation: 8,
+  );
+}