App para gerar frases

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

void main() {
  runApp(MaterialApp(
    home: new Home(),
    debugShowCheckedModeBanner: false,
  ));
}

class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {

  var _frases = [
    "Frase grandeeeeeeeeeeeeeeeeeeeeeeeeeeee 1",
    "Frase grandeeeeeeeeeeeeeeeeeeeeeeeeeeee 2",
    "Frase grandeeeeeeeeeeeeeeeeeeeeeeeeeeee 3",
    "Frase grandeeeeeeeeeeeeeeeeeeeeeeeeeeee 4"
  ];

  var _fraseGerada = "Clique abaixo para gerar uma frase!";

  void _gerarFrase() {
    var numeroSorteado = Random().nextInt(_frases.length);

    setState(() {
      _fraseGerada = _frases[ numeroSorteado ];
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: AppBar(
        title: new Text("Frases do dia"),
        backgroundColor: Colors.green,
      ),
      body: new Center(
        child: Container(
          padding: EdgeInsets.all(16),
          //width: double.infinity,
          /*decoration: BoxDecoration(
              border: new Border.all(width: 3, color: Colors.amber)
          ),*/
          child: Column(
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: <Widget>[
              Image.asset("images/logo.png"),
              new Text(
                _fraseGerada,
                textAlign: TextAlign.justify,
                style: TextStyle(
                    fontSize: 25,
                    fontStyle: FontStyle.italic,
                    color: Colors.black
                ),
              ),
              new RaisedButton(
                child: new Text(
                  "Nova Frase",
                  style: new TextStyle(
                      fontSize: 25,
                      color: Colors.white,
                      fontWeight: FontWeight.bold
                  ),
                ),
                color: Colors.green,
                onPressed: _gerarFrase,
              )
            ],
          ),
        )
      ),
    );
  }
}