import 'dart:async';
import 'dart:math';

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  const MyHomePage({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: SingleChildScrollView(
        child: Column(
          children: [
            const _Counter(),
            for (var i = 0; i < 15; i++)
              Container(
                height: 100,
                color: Color.fromRGBO(Random().nextInt(256), Random().nextInt(256), Random().nextInt(256), 1),
              ),
          ],
        ),
      ),
    );
  }
}

class _Counter extends StatefulWidget {
  const _Counter();

  @override
  State<_Counter> createState() => __CounterState();
}

class __CounterState extends State<_Counter> {
  int _count = 0;

  @override
  void initState() {
    Timer.periodic(const Duration(milliseconds: 500), (timer) {
      setState(() {
        _count++;
      });
    });
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Text('$_count');
  }
}