content: import 'package:flutter/material.dart';
  import 'package:url_launcher/url_launcher.dart';
  
  class Day81CheckboxListTile extends StatefulWidget {
    Day81CheckboxListTile({Key key}) : super(key: key);
  
    @override
    _Day81CheckboxListTileState createState() => _Day81CheckboxListTileState();
  }
  
  class _Day81CheckboxListTileState extends State<Day81CheckboxListTile> {
    var _isChecked = false;
  
    @override
    Widget build(BuildContext context) {
      return Scaffold(
        body: Center(
          // ? What is CheckboxListTile....
          // ! CheckboxListTile = CheckBox + ListTile....
          // We have all the ListTile property.....
          // And also the CheckBox property....
          child: CheckboxListTile(
            value: _isChecked, // ! here we added the value as bool....
            onChanged: (value) {
              // and manage the state ad the [onChanged] callback....
              setState(() {
                _isChecked = value;
              });
            },
            title: Text("Check Box!"), // ! here comes the title of [ListTile]....
            secondary: Icon(Icons
                .check), // ! and here is the secondary for the [ListTile]....
            controlAffinity: _isChecked
                ? ListTileControlAffinity.trailing
                : ListTileControlAffinity.leading,
          ),
        ),
        appBar: AppBar(
          title: Text('CheckboxListTile'),
          actions: <Widget>[
            IconButton(
              icon: Icon(Icons.help),
              onPressed: () async {
                const url =
                    'https://github.com/sanjaysanju618/100-Days-Of-Flutter-Widgets/' +
                        'blob/master/hundred_days_of_flutter_widget/' +
                        'lib/day081_checkbox_list_tile.dart';
                if (await canLaunch(url)) {
                  await launch(url);
                } else {
                  throw 'Could not launch $url';
                }
              },
            )
          ],
        ),
      );
    }
  }
  