Demonstrates Flutter widget lifecycle, state management, and UI composition.

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
	@override
	Widget build(BuildContext context) {
		return MaterialApp(
		title: 'Flutter Demo',
		theme: ThemeData(
			primarySwatch: Colors.blue,
			visualDensity: VisualDensity.adaptivePlatformDensity,
		),
		home: CounterScreen(),
		);
	}
}

class CounterScreen extends StatefulWidget {
	@override
	_CounterScreenState createState() => _CounterScreenState();
}

class _CounterScreenState extends State<CounterScreen> {
	int _counter = 0;
	List<String> _history = [];

	void _incrementCounter() {
		setState(() {
			_counter++;
			_history.add('Incremented to $_counter');
		});
	}

	void _decrementCounter() {
		setState(() {
			_counter--;
			_history.add('Decremented to $_counter');
		});
	}

	void _resetCounter() {
		setState(() {
			_counter = 0;
			_history.clear();
			_history.add('Counter reset');
		});
	}

	@override
	Widget build(BuildContext context) {
		return Scaffold(
			appBar: AppBar(
				title: Text('Flutter Counter'),
				backgroundColor: Theme.of(context).primaryColor,
			),
			body: Column(
				mainAxisAlignment: MainAxisAlignment.center,
				children: [
					Text(
						'Current Count:',
						style: Theme.of(context).textTheme.headlineSmall,
					),
					Text(
						'$_counter',
						style: Theme.of(context).textTheme.headlineLarge?.copyWith(
							color: Theme.of(context).primaryColor,
							fontWeight: FontWeight.bold,
						),
					),
					SizedBox(height: 20),
					Row(
						mainAxisAlignment: MainAxisAlignment.spaceEvenly,
						children: [
							FloatingActionButton(
								onPressed: _decrementCounter,
								tooltip: 'Decrement',
								child: Icon(Icons.remove),
								heroTag: 'decrement',
							),
							FloatingActionButton(
								onPressed: _resetCounter,
								tooltip: 'Reset',
								child: Icon(Icons.refresh),
								heroTag: 'reset',
							),
							FloatingActionButton(
								onPressed: _incrementCounter,
								tooltip: 'Increment',
								child: Icon(Icons.add),
								heroTag: 'increment',
							),
						],
					),
					SizedBox(height: 30),
					Expanded(
						child: Container(
							padding: EdgeInsets.all(16),
							child: Column(
								crossAxisAlignment: CrossAxisAlignment.start,
								children: [
									Text(
										'History:',
										style: Theme.of(context).textTheme.titleMedium,
									),
									Expanded(
										child: ListView.builder(
											itemCount: _history.length,
											itemBuilder: (context, index) {
												return ListTile(
													leading: Icon(Icons.history),
													title: Text(_history[index]),
													subtitle: Text('Action ${index + 1}'),
												);
											},
										),
									),
								],
							),
						),
					),
				],
			),
		);
	}
}