Flutter_Cookbook_ch_07_01_begin.dart

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

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Future Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: FuturePage(),
    );
  }
}

class FuturePage extends StatefulWidget {
  @override
  _FuturePageState createState() => _FuturePageState();
}

class _FuturePageState extends State<FuturePage> {
  String result;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Back from the Future'),
      ),
      body: Center(
        child: Column(children: [
          Spacer(),
          RaisedButton(
            child: Text('GO!'),
            onPressed: () {
            },
          ),
          Spacer(),
          Text(result.toString()),
          Spacer(),
          CircularProgressIndicator(),
          Spacer(),
        ]),
      ),
    );
  }
}