import 'package:flutter/material.dart';
import 'dart:async';

void main() {
  runApp(new MaterialApp(
    home: new MyApp()
  ));
}

class MyApp extends StatefulWidget {
  @override
  _State createState() => new _State();
}

enum Answers{YES, NO, MAYBE}

class _State extends State {

  String _value = '';

  void _setValue(String value) => setState(() => _value = value);

  Future _askUser() async {
    switch(
      await showDialog(
        context: context,
        child: new SimpleDialog(
          title: new Text("Do you like flutter?"),
          children: [
            new SimpleDialogOption(
              child: new Text("Yes"),
              onPressed: (){
                Navigator.pop(context, Answers.YES);
              },
            ),
            new SimpleDialogOption(
              child: new Text("No"),
              onPressed: (){
                Navigator.pop(context, Answers.NO);
              },
            ),
            new SimpleDialogOption(
              child: new Text("Maybe"),
              onPressed: (){
                Navigator.pop(context, Answers.MAYBE);
              },
            )
          ],
        )
      )
    ) {
      case Answers.YES:
        _setValue('Yes');
        break;
      case Answers.NO:
        _setValue("No");
        break;
      case Answers.MAYBE:
        _setValue("Maybe");
        break;
    }
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('Name here'),
      ),
      body: new Container(
        padding: new EdgeInsets.all(32.0),
        child: new Center(
          child: new Column(
            children: [
              new Text(_value),
              new RaisedButton(onPressed: () => _askUser(), child: new Text("Click me"),)
            ],
          ),
        ),
      ),
    );
  }
}