whatever.dart

import 'package:flutter/material.dart';

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

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Material App',
      routes: {
        '/': (context) => const Home(),
        '/whatever': (context) => Whatever(
            data: ModalRoute.of(context)!.settings.arguments as WhateverClass),
      },
    );
  }
}

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

  @override
  State<Home> createState() => _HomeState();
}

class _HomeState extends State<Home> {
  final whateverList = List.generate(
    Colors.primaries.length,
    (index) => WhateverClass(
      id: index,
      title: Colors.primaries[index].toString(),
      color: Colors.primaries[index],
    ),
  );
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Material App Bar'),
      ),
      body: ListView.builder(
        itemCount: whateverList.length,
        itemBuilder: (_, index) {
          final whateverVariable = whateverList[index];
          return ListTile(
            leading: Text('${whateverVariable.id}'),
            title: Text(whateverVariable.title),
            tileColor: whateverVariable.color,
            onTap: () {
              Navigator.of(context).pushNamed(
                '/whatever',
                arguments: whateverVariable,
              );
            },
          );
        },
      ),
    );
  }
}

class WhateverClass {
  final int id;
  final String title;
  final Color color;
  WhateverClass({required this.id, required this.title, required this.color});
}

class Whatever extends StatelessWidget {
  const Whatever({
    Key? key,
    required this.data,
  }) : super(key: key);
  final WhateverClass data;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: data.color,
      appBar: AppBar(title: Text(data.title)),
      body: Center(child: Text('${data.id}')),
    );
  }
}