error: The method 'onChanged' isn't defined for the type

Question

Expanded(
            child: Container(
              padding: const EdgeInsets.symmetric(horizontal: 20.0),
              decoration: const BoxDecoration(
                color: Colors.white,
                borderRadius: BorderRadius.only(
                  topLeft: Radius.circular(20.0),
                  topRight: Radius.circular(20.0),
                ),
              ),
              child: ListView(
                children: [
                  const ListTile(
                    title: Text('This is a task.'),
                    trailing: Checkbox(
                        value: false, onChanged: (value) => onChanged()),
                  ),
                ],
              ),
            ),
          ),

//I tried to delete onChanged but it doesn't work says OnCgange required. I am open any suggestion

Answer 1

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: SafeArea(
        child: Scaffold(
          body: Center(
            child: Expanded(
              child: Container(
                padding: const EdgeInsets.symmetric(horizontal: 20.0),
                decoration: const BoxDecoration(
                  color: Colors.white,
                  borderRadius: BorderRadius.only(
                    topLeft: Radius.circular(20.0),
                    topRight: Radius.circular(20.0),
                  ),
                ),
                child: ListView(
                  children: [
                    ListTile(
                      title: Text('This is a task.'),
                      trailing: Checkbox(
                        value: false,
                        onChanged: (value) => null,
                      ),
                    )
                  ],
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}

remove the cont value in front of the Listtile and modify unchanged function