Demo Code for handling toggle of switches in singles screen

ListPage.dart

import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';

class ListPage extends StatelessWidget{

  @override
  Widget build(_) => ListView.builder(
    itemCount: 2,
    itemBuilder: (_,itemPosition)=>_ItemView(index: itemPosition)
  );
}

class _ItemView extends StatefulWidget{
  final int index;

  const _ItemView({Key key,@required this.index}) : super(key: key);

  @override
  __ItemViewState createState() => __ItemViewState();
}

class __ItemViewState extends State<_ItemView> {
  bool value = false;

  @override
  Widget build(_) => ListTile(
    title: Text("Switch Widget ${widget.index}"),
    trailing: Switch(
      value: value,
      onChanged: (newValue)=>setState((){
        value = newValue;
      }),
    ),
  );
}