Passing data via Flutter Navigator

main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      home: HomePage(),
    );
  }
}

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("Home")),
      body: Center(
        child: ElevatedButton(
          child: const Text("Button"),
          onPressed: () {
            Navigator.of(context).push(
              MaterialPageRoute(
                builder: (context) => const NextPage("Passed data"),
              ),
            );
          },
        ),
      ),
    );
  }
}

class NextPage extends StatelessWidget {
  final String data;
  
  const NextPage(this.data);
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("Home")),
      body: Center(
        child: Text(data)
      ),
    );
  }
}