Flutter错误:在应用程序中间放置一个TabBar

Scaffold(
  appBar: AppBar(
    title: Text('Flutter App'),
  ),
  body: Center(
    child: Text('Content'),
  ),
  bottomNavigationBar: BottomNavigationBar(
    currentIndex: 0,
    items: [
      BottomNavigationBarItem(
        icon: Icon(Icons.home),
        label: 'Home',
      ),
      BottomNavigationBarItem(
        icon: Icon(Icons.settings),
        label: 'Settings',
      ),
    ],
    onTap: (index) {
      // 处理导航项点击事件
    },
  ),
)

Scaffold(
  appBar: AppBar(
    title: Text('Flutter App'),
  ),
  body: Column(
    children: [
      Expanded(
        child: Center(
          child: Text('Content'),
        ),
      ),
      TabBar(
        tabs: [
          Tab(text: 'Tab 1'),
          Tab(text: 'Tab 2'),
        ],
      ),
    ],
  ),
)