import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      home: MyWidget(),
    ),
  );
}

class MyWidget extends StatefulWidget {
  const MyWidget({Key? key}) : super(key: key);

  @override
  State<MyWidget> createState() => _MyWidgetState();
}

class _MyWidgetState extends State<MyWidget> {
  bool? isChecked = false;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: CheckboxListTile(
          activeColor: Colors.orange,
          checkColor: Colors.yellow,
          controlAffinity: ListTileControlAffinity.leading,
          tristate: true,
          title: const Text('クリックして'),
          subtitle: const Text('これはReinのテストです'),
          value: isChecked,
          onChanged: (value) {
            setState(() {
              isChecked = value;
            });
          },
        ),
      ),
    );
  }
}