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// 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.
import 'package:flutter/material.dart';
/// Flutter code sample for [Autocomplete] that shows how to fetch the options
/// from a remote API.
const Duration fakeAPIDuration = Duration(seconds: 1);
void main() => runApp(const AutocompleteExampleApp());
class AutocompleteExampleApp extends StatelessWidget {
const AutocompleteExampleApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('Autocomplete - async'),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text('Type below to autocomplete the following possible results: ${_FakeAPI._kOptions}.'),
const _AsyncAutocomplete(),
],
),
),
),
);
}
}
class _AsyncAutocomplete extends StatefulWidget {
const _AsyncAutocomplete();
@override
State<_AsyncAutocomplete > createState() => _AsyncAutocompleteState();
}
class _AsyncAutocompleteState extends State<_AsyncAutocomplete > {
// The query currently being searched for. If null, there is no pending
// request.
String? _searchingWithQuery;
// The most recent options received from the API.
late Iterable<String> _lastOptions = <String>[];
@override
Widget build(BuildContext context) {
return Autocomplete<String>(
optionsBuilder: (TextEditingValue textEditingValue) async {
_searchingWithQuery = textEditingValue.text;
final Iterable<String> options = await _FakeAPI.search(_searchingWithQuery!);
// If another search happened after this one, throw away these options.
// Use the previous options intead and wait for the newer request to
// finish.
if (_searchingWithQuery != textEditingValue.text) {
return _lastOptions;
}
_lastOptions = options;
return options;
},
onSelected: (String selection) {
debugPrint('You just selected $selection');
},
);
}
}
// Mimics a remote API.
class _FakeAPI {
static const List<String> _kOptions = <String>[
'aardvark',
'bobcat',
'chameleon',
];
// Searches the options, but injects a fake "network" delay.
static Future<Iterable<String>> search(String query) async {
await Future<void>.delayed(fakeAPIDuration); // Fake 1 second delay.
if (query == '') {
return const Iterable<String>.empty();
}
return _kOptions.where((String option) {
return option.contains(query.toLowerCase());
});
}
}