Flutter : Column is not support under DraggableScrollbar - flutter

Question

this is a page of TabBarView(). I want to add some text or container(), top of the ListView.builder(). Which is scroll-able with ListView.builder(). But column() isn't supported as child of DraggableScrollbar(). Why isn't it supported it here ?
How can I add Text() or any container(), before starting ListView.builder() widget ?
import 'package:boimarket/booksdescription.dart';
import 'package:boimarket/model/model.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:draggable_scrollbar/draggable_scrollbar.dart';
class StoryBooksCategory extends StatelessWidget {
final ScrollController controller;
const StoryBooksCategory({Key key, #required this.controller})
: super(key: key);
#override
Widget build(BuildContext context) {
var _height = MediaQuery.of(context).size.height;
var _width = MediaQuery.of(context).size.width;
final Color _whiteCream = Color.fromRGBO(250, 245, 228, 1);
final Color _darkBlue = Color.fromRGBO(0, 68, 69, 1);
return Align(
alignment: Alignment.topCenter,
child: Container(
width: _width / 1.1,
child: FutureBuilder(
future: fetchBooks(),
builder: (context, AsyncSnapshot<List<Book>> snapshot) {
if (!snapshot.hasData) {
return Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
LinearProgressIndicator(
backgroundColor: _whiteCream,
),
Text("Loading"),
],
);
} else(snapshot.hasData) {
var storyBooks =
snapshot.data.where((b) => b.category == 1).toList();
storyBooks.sort((a, b) => a.name.compareTo(b.name));
print(storyBooks.length);
return DraggableScrollbar.rrect(
controller: controller,
backgroundColor: _darkBlue,
child: Column(
children: [
Text("I want to add some text here"),
ListView.builder(
controller: controller,
scrollDirection: Axis.vertical,
itemCount: storyBooks.length,
itemBuilder: (context, index) {
return GestureDetector(
onTap: () {
Route route = MaterialPageRoute(
builder: (context) => BookDescription(
storyBooksValue: storyBooks[index]),
);
Navigator.push(context, route);
},
child: Padding(
padding: const EdgeInsets.only(
left: 10.0, right: 10.0, top: 20.0),
child: Container(
width: _width / 1.1,
height: _height / 4,
decoration: BoxDecoration(
color: _whiteCream,
borderRadius: BorderRadius.all(
Radius.circular(5.0),
),
boxShadow: [
BoxShadow(
color: Colors.black26,
blurRadius: 2,
spreadRadius: 2,
offset: Offset(2.0, 2.0),
)
],
),
),
),
),
},
),
],
),
),
},
},
),
),
),
},
}