如何将底部可扩展抽屉放置到特定选项卡

Question

我有一个底部可扩展抽屉和三个选项卡，底部可扩展抽屉对于所有三个选项卡都是可见的，但是我希望它在特定的选项卡上可见。 树形标签-

class B1Home extends StatefulWidget {
  @override
  _B1HomeState createState() => _B1HomeState();
}

class _B1HomeState extends State<B1Home> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: Stack(
        children: <Widget>[
          SafeArea(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: <Widget>[
                SizedBox(height: 8),
                Header(),
                SizedBox(height: 20),
                Tabs(refresh: () => setState(() {})),
                value == 0 ? Center(child: AbcPage()) : Container(),
                value == 1 ? Center(child: SlidingCardsView()) : Container(),
                value == 2 ? Center(child: GhiPage()) : Container(),
              ],
            ),
          ),
          ExhibitionBottomSheet()
        ],
      ),
    );
  }
}

ExhibitionBottomSheet（）是底部可扩展的抽屉，当前可用于所有三个选项卡，因为它位于其中的选项卡小部件下方，我希望仅对SlidingCardsView（）可见。我试图将其从标签页并将其添加到SlidingCardsView页，但它会给出定位错误。

SlidingCardsView Page-
class SlidingCardsView extends StatefulWidget {
  @override
  _SlidingCardsViewState createState() => _SlidingCardsViewState();
}

class _SlidingCardsViewState extends State<SlidingCardsView> {
  PageController pageController;
  double pageOffset = 0;

  @override
  void initState() {
    super.initState();
    pageController = PageController(viewportFraction: 0.8);
    pageController.addListener(() {
      setState(() => pageOffset = pageController.page);
    });
  }

  @override
  void dispose() {
    pageController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
  return Stack(
      children:<Widget>[
       SafeArea(
      child:Column(
//        crossAxisAlignment: CrossAxisAlignment.start,
      children: <Widget>[

        SizedBox(

          height: MediaQuery.of(context).size.height * 0.55,
          child: PageView(

            controller: pageController,
            children: <Widget>[
              SlidingCard(
                  name: 'ORIENTATION DAY 2019',
                  date: '02-06-2019',
                  assetName: 'steve-johnson.jpeg',
                  offset: pageOffset,
                  onTap: AbcPage()
              ),
              SlidingCard(
                  name: 'SPORTS DAY 2018',
                  date: '18-11-2018',
                  assetName: 'rodion-kutsaev.jpeg',
                  offset: pageOffset - 1,
                  onTap: AbcPage()


              ),

            ],

          ),

        ),
       /* Positioned(bottom:  147.6,
          child: ExhibitionBottomSheet())
        //ExhibitionBottomSheet()
*/
       //Align(alignment: Alignment.bottomCenter,child: ExhibitionBottomSheet(),)
      ExhibitionBottomSheet()
      ],
    ),

       ),
        //Align(alignment: Alignment.bottomCenter,child: ExhibitionBottomSheet(),)

        //ExhibitionBottomSheet()
     ]
    );
    //ExhibitionBottomSheet()

  }
}

我尝试了各种方法来放置ExhibitionBottomSheet（），但都给出了定位错误。