Answer for https://stackoverflow.com/questions/61674632/how-can-i-return-the-value-that-a-statefellwigdet-contains-to-use-it-in-a-listvi

main.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: ListViewBuilder(),
    );
  }
}

class RadioButtom extends StatefulWidget {
  @override
  _RadioButtomState createState() => _RadioButtomState();

  RadioButtom({this.value, this.onChanged});

  final bool value;
  final ValueChanged<bool> onChanged;
}

class _RadioButtomState extends State<RadioButtom> {
  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        Radio(
          value: true,
          groupValue: widget.value,
          onChanged: widget.onChanged,
        ),
        Text(
          'Yes',
          style: TextStyle(
            fontSize: 12.0,
            fontFamily: "OpenSans-Regular",
          ),
        ),
        Radio(
          value: false,
          groupValue: widget.value,
          onChanged: widget.onChanged,
        ),
        Text(
          'No',
          style: TextStyle(
            fontSize: 12.0,
            fontFamily: "OpenSans-Regular",
          ),
        )
      ],
    );
  }
}

class ListViewBuilder extends StatefulWidget {
  @override
  _ListViewBuilderState createState() => _ListViewBuilderState();
}

class _ListViewBuilderState extends State<ListViewBuilder> {
  final _itemCount = 10;
  List<bool> _radios;

  @override
  initState() {
    super.initState();
    _radios = List<bool>.filled(_itemCount, false);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ListView.builder(
        itemCount: _itemCount,
        itemBuilder: (context, index) => RadioButtom(
            value: _radios[index],
            onChanged: (value) {
              setState(() {
                _radios[index] = value;
              });
            }),
      ),
    );
  }
}