Flutter - Autocomplete with displaying selected item information on screen - flutter

Question

I'm trying to implement Autocomplete text, then display records related to selected item. For example, If I select 'IBM' from below example, display records related to IBM in a listview.
Autocomplete is working as expected but upon selecting the item list view is not generating. i.e. in onSelected(), widget buildPositions() should be corrected, any help would be highly appreciated.
import 'package:e2/Models/model_positions.dart';
import 'package:flutter/material.dart';
class ContractControl extends StatefulWidget {
const ContractControl({super.key});
#override
State<ContractControl> createState() => _ContractControlState();
}
class _ContractControlState extends State<ContractControl> {
List<dynamic> _selectedItems = [];
static const List<String> listItems = <String>['TCS', 'IBM', 'WIPRO'];
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("Contract Control"),
centerTitle: true,
//automaticallyImplyLeading: false,
),
body: Autocomplete(optionsBuilder: (TextEditingValue textEditingValue) {
if (textEditingValue.text == '') {
return const Iterable<String>.empty();
}
return listItems.where((String item) {
return item.contains(textEditingValue.text.toUpperCase());
});
}, onSelected: (String item) {
buildPositions(item);
}));
}
## *****************need correction here ******************
Widget buildPositions(String item) {
return Container(
child: FutureBuilder<List<dynamic>>(
future: ModelsPositions().detailedContractControlData(item),
builder: (context, snapshot) {
if (snapshot.hasData) {
List<dynamic> positions = snapshot.data ?? [];
return ListView.builder(
itemCount: positions.length,
itemBuilder: (context, index) {
return Card(
child: Row(children: [
Checkbox(
value: _selectedItems.contains(positions[index]),
onChanged: (value) {
setState(() {
if (value == null) {
return null;
}
if (value) {
_selectedItems.add(positions[index]);
} else {
_selectedItems
.removeWhere((item) => item == positions[index]);
}
});
},
),
]));
},
);
} else if (snapshot.hasError) {
return Center(
child: Text('Failed to fetch Positions Summary'),
);
}
return Center(
child: CircularProgressIndicator(),
);
},
),
);
}
}