ListView 单独使用的时候，解决不能删除上边边距

MediaQuery.removePadding(
                removeTop: true,
                context: context,
                child: ListView.builder(
                  itemCount: itemCount,
                  itemBuilder: (con,index){
                    print(data[index]);
                      return OrderItem(Order.fromJson(data[index]));
                    //return OrderListItem(order: Order.fromJson(data[index]),);
                  },
                )
            )