fix: 修复导航栏消失问题 - BottomNavigationBar 添加 type: fixed 和选中颜色 - activity_list_screen 移除嵌套 Scaffold

lib/screens/activity_list_screen.dart

@@ -78,23 +78,27 @@ class _ActivityListScreenState extends State<ActivityListScreen> {
 
   @override
   Widget build(BuildContext context) {
-    return Scaffold(
-      backgroundColor: const Color(0xFFFFF8F0),
-      appBar: AppBar(
-        title: Text('伴享', style: TextStyle(fontWeight: FontWeight.bold)),
-        centerTitle: true,
-        actions: [
-          IconButton(
-            icon: Icon(Icons.search),
-            onPressed: () {},
-          ),
-          IconButton(
-            icon: Icon(Icons.notifications_none),
-            onPressed: () {},
+    return Container(
+      color: const Color(0xFFFFF8F0),
+      child: Column(
+        children: [
+          AppBar(
+            title: Text('伴享', style: TextStyle(fontWeight: FontWeight.bold)),
+            centerTitle: true,
+            actions: [
+              IconButton(
+                icon: Icon(Icons.search),
+                onPressed: () {},
+              ),
+              IconButton(
+                icon: Icon(Icons.notifications_none),
+                onPressed: () {},
+              ),
+            ],
           ),
+          Expanded(child: _buildFeed()),
         ],
       ),
-      body: _buildFeed(),
     );
   }
 

lib/screens/main_screen.dart

@@ -32,8 +32,11 @@ class _MainScreenState extends State<MainScreen> {
       floatingActionButton: _buildGlobalFab(),
       floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked,
       bottomNavigationBar: BottomNavigationBar(
+        type: BottomNavigationBarType.fixed,
         currentIndex: _currentIndex,
         onTap: (i) => setState(() => _currentIndex = i),
+        selectedItemColor: const Color(0xFFFF6B35),
+        unselectedItemColor: const Color(0xFF999999),
         items: const [
           BottomNavigationBarItem(icon: Icon(Icons.home_outlined), activeIcon: Icon(Icons.home), label: '首页'),
           BottomNavigationBarItem(icon: Icon(Icons.people_outline), activeIcon: Icon(Icons.people), label: '好友'),