我尝试了flutter_adaptive_scaffold中使用的示例，但使用了Appbar小部件并将useDrawer设置为true。小部件只出现在我调整到移动的大小（我在网上运行）

AdaptiveScaffold(
      // An option to override the default breakpoints used for small, medium,
      // and large.
      smallBreakpoint: const WidthPlatformBreakpoint(end: 700),
      mediumBreakpoint: const WidthPlatformBreakpoint(begin: 700, end: 1000),
      largeBreakpoint: const WidthPlatformBreakpoint(begin: 1000),
      useDrawer: true,
      appBar: AppBar(title: const Text("My App")),
      selectedIndex: _selectedTab,
      onSelectedIndexChange: (int index) {
        setState(() {
          _selectedTab = index;
        });
      },
      destinations: const <NavigationDestination>[
        NavigationDestination(
          icon: Icon(Icons.inbox_outlined),
          selectedIcon: Icon(Icons.inbox),
          label: 'Inbox',
        ),
        NavigationDestination(
          icon: Icon(Icons.article_outlined),
          selectedIcon: Icon(Icons.article),
          label: 'Articles',
        ),
        NavigationDestination(
          icon: Icon(Icons.chat_outlined),
          selectedIcon: Icon(Icons.chat),
          label: 'Chat',
        ),
        NavigationDestination(
          icon: Icon(Icons.video_call_outlined),
          selectedIcon: Icon(Icons.video_call),
          label: 'Video',
        ),
        NavigationDestination(
          icon: Icon(Icons.home_outlined),
          selectedIcon: Icon(Icons.home),
          label: 'Inbox',
        ),
      ],
      body: (_) => GridView.count(crossAxisCount: 2, children: children),
      smallBody: (_) => ListView.builder(
        itemCount: children.length,
        itemBuilder: (_, int idx) => children[idx],
      ),
      // Define a default secondaryBody.
      secondaryBody: (_) => Container(
        color: const Color.fromARGB(255, 234, 158, 192),
      ),
      // Override the default secondaryBody during the smallBreakpoint to be
      // empty. Must use AdaptiveScaffold.emptyBuilder to ensure it is properly
      // overridden.
      smallSecondaryBody: AdaptiveScaffold.emptyBuilder,
    )

我尝试寻找一个选项，使Appbar始终可见，但我找不到它