Flutter assignment #1

import 'package:flutter/material.dart';

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

class App extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
          appBar: AppBar(
            title: Text('My fun app'),
          ),
          body: TextWidget()),
    );
  }
}

class TextWidget extends StatefulWidget {
  @override
  _TextWidgetState createState() => _TextWidgetState();
}

class _TextWidgetState extends State<TextWidget> {

  var _text = 'Hello';

  void _changeText() {
    setState(() {
      _text = 'How are you ?';
    });
  }

  @override
  Widget build(BuildContext context) {
    return Column(children: <Widget>[
      Text(_text),
      TextController('Change text', _changeText)
    ]);
  }
}


class TextController extends StatelessWidget {

  final String _label;
  final Function _changeHandler;

  TextController(this._label, this._changeHandler);

  @override
  Widget build(BuildContext context) {
    return RaisedButton(onPressed: _changeHandler, child: Text(_label),);
  }
}