passing_values.dart

import 'package:flutter/material.dart';

final Color darkBlue = Color.fromARGB(255, 18, 32, 47);

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
      debugShowCheckedModeBanner: false,
      home: const Scaffold(body: Center(child: Home())),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Button(
      // onPreesed: print,
      // onPreesed: (value) => print(value),
      onPreesed: (value) {
        print(value);
      },
    );
  }
}

class Button extends StatelessWidget {
  const Button({
    Key? key,
    required this.onPreesed,
  }) : super(key: key);
  final ValueChanged<String> onPreesed;
  @override
  Widget build(BuildContext context) {
    return ElevatedButton(
      onPressed: () => onPreesed('You are gonna die for pressing me'),
      child: const Text("Don't press me"),
    );
  }
}