隐藏滚动条上的Appbar？

如果我对您的理解正确，以下代码应可使应用程序栏在滚动时隐藏，而TabBar仍可见：

new Scaffold(  body: new NestedScrollView(    controller: _scrollViewController,    headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {      return <Widget>[        new SliverAppBar(          title: new Text(widget.title),          pinned: true,          floating: true,          forceElevated: innerBoxIsScrolled,          bottom: new TabBar( tabs: <Tab>[   new Tab(text: "STATISTICS"),   new Tab(text: "HISTORY"), ], controller: _tabController,          ),        ),      ];    },    body: new TabBarView(      children: <Widget>[        new StatisticsPage(),        new HistoryPage(),      ],      controller: _tabController,    ),  ),);

示例来自于。这篇文章.