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@hanskokx
Last active July 31, 2022 17:26
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Stream example
import 'dart:convert';
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:http/http.dart';
void main() => runApp(const MyApp());
Client http = Client();
final StreamController streamController = StreamController();
Future<Album> createAlbum(String title) async {
final response = await http.post(
Uri.parse('https://jsonplaceholder.typicode.com/albums'),
headers: <String, String>{
'Content-Type': 'application/json; charset=UTF-8',
},
body: jsonEncode(<String, String>{
'title': title,
}),
);
if (response.statusCode != 201) {
throw Exception('Failed to create album.');
}
return Album.fromJson(jsonDecode(response.body));
}
Future<Album> fetchAlbum({required int id}) async {
final Response response = await http
.get(Uri.parse('https://jsonplaceholder.typicode.com/albums/$id'));
if (response.statusCode != 200) {
throw Exception('There was an error fetching the album.');
}
final Map<String, dynamic> data = jsonDecode(response.body);
final Album album = Album.fromJson(data);
return album;
}
void fetchAlbums() async {
final List<int> albumsToFetch = List<int>.generate(10, (k) => k + 1);
for (final int albumToFetch in albumsToFetch) {
final Album album = await fetchAlbum(id: albumToFetch);
streamController.sink.add(album);
}
}
class Album {
int? userId;
int? id;
String? title;
Album({this.userId, this.id, this.title});
factory Album.fromJson(Map<String, dynamic> json) => Album(
userId: json["userId"],
id: json["id"],
title: json["title"],
);
}
class AlbumList extends StatefulWidget {
const AlbumList({Key? key}) : super(key: key);
@override
_AlbumListState createState() => _AlbumListState();
}
class _AlbumListState extends State<AlbumList> {
final List<Album> _albums = [];
@override
Widget build(BuildContext context) {
return StreamBuilder(
stream: streamController.stream,
builder: (BuildContext context, AsyncSnapshot snapshot) {
if (snapshot.hasData) {
_albums.add(snapshot.data);
}
return ListView.builder(
shrinkWrap: true,
itemCount: _albums.length,
itemBuilder: (BuildContext context, int index) {
return Card(
child: Padding(
padding: const EdgeInsets.all(8),
child: Text(_albums[index].title ?? "Undefined"),
),
);
},
);
},
);
}
@override
void initState() {
super.initState();
fetchAlbums();
}
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const Home(),
);
}
}
class Home extends StatelessWidget {
const Home({
Key? key,
}) : super(key: key);
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Albums'),
),
floatingActionButtonLocation: FloatingActionButtonLocation.startFloat,
floatingActionButton: FloatingActionButton(
onPressed: () async {
final String? title = await _userInputDialog(context);
if (title == null) {
throw Exception('Cancelled Album creation.');
}
if (title.isNotEmpty) {
final Album album = await createAlbum(title);
streamController.sink.add(album);
print("Created new album! ${album.title}");
}
},
child: const Icon(Icons.add),
),
body: const AlbumList(),
);
}
}
Future<String?> _userInputDialog(BuildContext context) async {
return await showDialog<String>(
context: context,
builder: (BuildContext context) {
return SimpleDialog(
title: const Text('Create Album'),
contentPadding: const EdgeInsets.all(24),
children: [
TextFormField(
decoration: const InputDecoration(
hintText: "Album name",
),
onFieldSubmitted: (String? value) {
Navigator.pop(context, value);
},
),
],
);
},
);
}
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