Different between StatelessWidget and StatefulWidget in flutter

Code for StatelessWidget

	// this example is created by slcoder to explain statelessWidget in slcoder's tutorials.
	// goto raised button example gist to get statefulWidget code
	import 'package:flutter/material.dart';
	void main() => runApp(new MyApp());
	int count = 0;
	class MyApp extends StatelessWidget {
	void _increase() {
	count++;
	}
	@override
	Widget build(BuildContext context) {
	return new MaterialApp(
	title: 'Hello World App',
	home: new Scaffold(
	appBar: new AppBar(
	title: new Text('StatelessWidget'),
	backgroundColor: new Color(0xFF8B1122),
	),
	body: new Center(
	child: new Column(
	mainAxisAlignment: MainAxisAlignment.center,
	children: <Widget>[
	new Text(
	"Up Votes : $count",
	style: new TextStyle(
	fontSize: 25.0,
	color: new Color(0xFF8B1122),
	fontWeight: FontWeight.w600,
	),
	),
	new RaisedButton(
	child: new Text('Vote up', style: new TextStyle(fontSize: 20.0,)),
	color: new Color(0xFF8B1122),
	textColor: Colors.white,
	padding: const EdgeInsets.symmetric(vertical: 10.0, horizontal: 30.0),
	elevation: 10.0,
	splashColor: Colors.white70,
	onPressed: _increase,
	),
	],
	),
	),
	),
	);
	}
	}

view raw statelesswidget_example.dart hosted with ❤ by GitHub

Code for StatefulWidget

	// this example is created by slcoder to explain statefulWidget in slcoder's tutorials.
	import 'package:flutter/material.dart';
	void main() => runApp(new MyApp());
	int _count = 0;
	class MyApp extends StatefulWidget {
	_HomePage createState() => new _HomePage();
	}
	class _HomePage extends State<MyApp> {
	void _increase() {
	setState(() => _count++);
	}
	@override
	Widget build(BuildContext context) {
	return new MaterialApp(
	title: 'Hello World App',
	home: new Scaffold(
	appBar: new AppBar(
	title: new Text('StatelessWidget'),
	backgroundColor: new Color(0xFF8B1122),
	),
	body: new Center(
	child: new Column(
	mainAxisAlignment: MainAxisAlignment.center,
	children: <Widget>[
	new Text(
	"Up Votes : $_count",
	style: new TextStyle(
	fontSize: 25.0,
	color: new Color(0xFF8B1122),
	fontWeight: FontWeight.w600,
	),
	),
	new RaisedButton(
	child: new Text('Vote up', style: new TextStyle(fontSize: 20.0,)),
	color: new Color(0xFF8B1122),
	textColor: Colors.white,
	padding: const EdgeInsets.symmetric(vertical: 10.0, horizontal: 40.0),
	elevation: 10.0,
	splashColor: Colors.white70,
	onPressed: _increase,
	),
	],
	),
	),
	),
	);
	}
	}

view raw statefulwidget_example.dart hosted with ❤ by GitHub