Firestore 中的商品未显示在 Flutter 购物车中

Question

我读取了用户内容 (userCart) 列表 Item 并将 shortInfo 读取为用户添加到购物车的产品的 ID，因此我可以看到项目的总价，但它不工作。

我认为它是可读的，如果有人能理解这个问题，请帮助我

child: Scaffold(


    drawer: MyDrawer(),
    //checkout button
    floatingActionButton: FloatingActionButton.extended(
      elevation: 10.0,
      label: Text("Check Out"),
      icon: Icon(Icons.navigate_next),
      backgroundColor: Colors.pinkAccent,

      onPressed: (){

        if(EcommerceApp.sharedPreferences.getStringList(EcommerceApp.userCartList).length == 1)

        {
           Fluttertoast.showToast(msg: "Your Cart is empty!");
        }
        else
          {
            Route route = MaterialPageRoute(

                builder: (_) => Address(totalAmount: totalAmount,));

            Navigator.pushReplacement(context, route);
          }
      },
    ),
    appBar:MyAppBar(),

    body: CustomScrollView(
      slivers: [
        // total price of items
        SliverToBoxAdapter(

          child: Consumer2<TotalAmount, CartItemCounter>(

              builder: (context, amountProvider, cartProvider, c){
                return Padding(
                  padding: EdgeInsets.all(8.0),

                  child: Center(
                    child: cartProvider.count == 0

                    ? Container()
                    : Text("Total Price: \$${amountProvider.totalAmount.toString()}",

                    style: TextStyle(

                      color: Colors.black,

                      fontSize: 20.0,

                      fontWeight: FontWeight.w700,

                    ),
                    ),
                  ),
                );
              }
          ),
        ),

        //items in the cart page

        StreamBuilder<QuerySnapshot>(

            stream: EcommerceApp.firestore.collection("/items")

          .where("shortInfo", whereIn:EcommerceApp.sharedPreferences.getStringList(EcommerceApp.userCartList)).snapshots(),

          builder: (context, snapshots){
              return !snapshots.hasData
                     ? SliverToBoxAdapter(child: Center(child: circularProgress(),),)
                     : snapshots.data.documents.length == 0
                     ? beginBuildinCart()
                     : SliverList(
                       delegate: SliverChildBuilderDelegate(
                           (context, index)
                               {
                                 ItemModel model = ItemModel.fromJson(snapshots.data.documents[index].data);
                                 if(index == 0){
                                   totalAmount = 0;
                                   totalAmount = model.price + totalAmount;
                                 }
                                 else
                                   {
                                     totalAmount = model.price + totalAmount;
                                   }
                                 if(snapshots.data.documents.length - 1 == index){
                                   WidgetsBinding.instance.addPostFrameCallback((t) {
                                     Provider.of<TotalAmount>(context, listen: false).display(totalAmount);
                                   });
                                 }
                                 return sourceInfo(model, context, removeCartFunction: () => removeItemFromUserCart(model.shortInfo) );
                               },
                               childCount: snapshots.hasData ? snapshots.data.documents.length : 0
                       ),
                    );
          },
        ),
      ],
    ),
  ),
);
}
beginBuildinCart(){

}
removeItemFromUserCart(String shortInfoAsId){

}
}