// Copyright 2014 The Flutter Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. // Flutter code sample for FutureBuilder import 'package:flutter/material.dart'; void main() => runApp(const MyApp()); class MyApp extends StatelessWidget { const MyApp({Key? key}) : super(key: key); static const String _title = 'Flutter Code Sample'; @override Widget build(BuildContext context) { return const MaterialApp( title: _title, home: MyStatefulWidget(), ); } } class MyStatefulWidget extends StatefulWidget { const MyStatefulWidget({Key? key}) : super(key: key); @override State<MyStatefulWidget> createState() => _MyStatefulWidgetState(); } class _MyStatefulWidgetState extends State<MyStatefulWidget> { final Future<String> _calculation = Future<String>.delayed( const Duration(seconds: 2), () => 'Data Loaded', ); @override Widget build(BuildContext context) { return DefaultTextStyle( style: Theme.of(context).textTheme.headline2!, textAlign: TextAlign.center, child: FutureBuilder<String>( future: _calculation, // a previously-obtained Future<String> or null builder: (BuildContext context, AsyncSnapshot<String> snapshot) { List<Widget> children; if (snapshot.hasData) { children = <Widget>[ const Icon( Icons.check_circle_outline, color: Colors.green, size: 60, ), Padding( padding: const EdgeInsets.only(top: 16), child: Text('Result: ${snapshot.data}'), ) ]; } else if (snapshot.hasError) { children = <Widget>[ const Icon( Icons.error_outline, color: Colors.red, size: 60, ), Padding( padding: const EdgeInsets.only(top: 16), child: Text('Error: ${snapshot.error}'), ) ]; } else { children = const <Widget>[ SizedBox( width: 60, height: 60, child: CircularProgressIndicator(), ), Padding( padding: EdgeInsets.only(top: 16), child: Text('Awaiting result...'), ) ]; } return Center( child: Column( mainAxisAlignment: MainAxisAlignment.center, children: children, ), ); }, ), ); } }