Flutter - Updating Data on the Internet
Last Updated :
15 Jul, 2025
In today's world, most applications heavily rely on fetching and updating information from the servers through the internet. In Flutter, such services are provided by the http package. In this article, we will explore the same. Let's see a sample video of what we are going to develop.
Sample Video:
Step-by-Step Implementation
Step 1: Create a new Flutter Application
Create a new Flutter application using the command Prompt. To create a new app, write the following command and run it.
flutter create app_name
To know more about it refer this article: Creating a Simple Application in Flutter
Step 2: Adding the Dependency
To add the dependency to the pubspec.yaml file, add http as a dependency in the dependencies part of the pubspec.yaml file, as shown below:
Dart
dependencies:
flutter:
sdk: flutter
http: ^1.3.0
Now, run the command below in the terminal.
flutter pub get
Or
Run the command below in the terminal.
flutter pub add http
Step 3: Import dependencies
To use libraries, import all of them in the respective .dart file.
import 'package:http/http.dart' as http;
Step 4: Start Coding
- Update Data over the Internet
Use the http.put() method to update the title of the Album in JSONPlaceholder as shown below:
Dart
Future<Album> updateAlbum(String title) async {
final http.Response response = await http.put(
Uri.parse('https://jsonplaceholder.typicode.com/albums/1'),
headers: <String, String>{
'Content-Type': 'application/json; charset=UTF-8',
},
body: jsonEncode(<String, String>{
'title': title,
}),
);
- Converting the Response
Though making a network request is no big deal, working with the raw response data can be inconvenient. To make your life easier, convert the raw data (ie, http.response) into a Dart object. Here we will create an Album class that contains the JSON data as shown below:
Dart
class Album {
final int id;
final String title;
Album({required this.id, required this.title});
factory Album.fromJson(Map<String, dynamic> json) {
return Album(
id: json['id'],
title: json['title'],
);
}
}
- Convert http.Response to an Album
Now, follow the steps below to update the fetchAlbum() function to return a Future<Album>:
- Use the dart:convert package to convert the response body into a JSON Map.
- Use the fromJSON() factory method to convert JSON Map into Album if the server returns an OK response with a status code of 200.
- Throw an exception if the server doesn't return an OK response with a status code of 200.
Dart
Future<Album> updateAlbum(String title) async {
final http.Response response = await http.put(
Uri.parse('https://jsonplaceholder.typicode.com/albums/1'),
headers: <String, String>{
'Content-Type': 'application/json; charset=UTF-8',
},
body: jsonEncode(<String, String>{
'title': title,
}),
);
// parsing JSOn or throwing an exception
if (response.statusCode == 200) {
return Album.fromJson(json.decode(response.body));
} else {
throw Exception('Failed to update album.');
}
}
- Fetching the Data
Now use the fetch() method to fetch the data as shown below:
Dart
Future<Album> fetchAlbum() async {
final response = await http
.get(Uri.parse('https://jsonplaceholder.typicode.com/albums/1'));
// Dispatch action depending upon
//the server response
if (response.statusCode == 200) {
return Album.fromJson(json.decode(response.body));
} else {
throw Exception('Failed to load album');
}
}
- Update the existing Data through user input
Now create a TextField for the user to enter a title and a RaisedButton to send data to the server. Also, define a TextEditingController to read the user input from a TextField as shown below:
Dart
Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(snapshot.data!.title),
TextField(
controller: _controller,
decoration:
const InputDecoration(hintText: 'Enter Title'),
),
ElevatedButton(
child: const Text('Update Data'),
onPressed: () {
setState(() {
_futureAlbum = updateAlbum(_controller.text);
});
},
)
- Displaying the Data
Use the FlutterBuilder widget to display the data on the screen as shown below:
Dart
FutureBuilder<Album>(
future: _futureAlbum,
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
if (snapshot.hasData) {
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(snapshot.data!.title),
TextField(
controller: _controller,
decoration:
const InputDecoration(hintText: 'Enter Title'),
),
ElevatedButton(
child: const Text('Update Data'),
onPressed: () {
setState(() {
_futureAlbum = updateAlbum(_controller.text);
});
},
)
],
);
} else if (snapshot.hasError) {
return Text("${snapshot.error}");
}
}
return const CircularProgressIndicator();
},
),
Complete Source Code:
Dart
import 'dart:async';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
Future<Album> fetchAlbum() async {
final response = await http
.get(Uri.parse('https://jsonplaceholder.typicode.com/albums/1'));
// Dispatch action depending upon
//the server response
if (response.statusCode == 200) {
return Album.fromJson(json.decode(response.body));
} else {
throw Exception('Failed to load album');
}
}
Future<Album> updateAlbum(String title) async {
final http.Response response = await http.put(
Uri.parse('https://jsonplaceholder.typicode.com/albums/1'),
headers: <String, String>{
'Content-Type': 'application/json; charset=UTF-8',
},
body: jsonEncode(<String, String>{
'title': title,
}),
);
// parsing JSOn or throwing an exception
if (response.statusCode == 200) {
return Album.fromJson(json.decode(response.body));
} else {
throw Exception('Failed to update album.');
}
}
class Album {
final int id;
final String title;
Album({required this.id, required this.title});
factory Album.fromJson(Map<String, dynamic> json) {
return Album(
id: json['id'],
title: json['title'],
);
}
}
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);
@override
// ignore: library_private_types_in_public_api
_MyAppState createState() {
return _MyAppState();
}
}
class _MyAppState extends State<MyApp> {
final TextEditingController _controller = TextEditingController();
late Future<Album> _futureAlbum;
@override
void initState() {
super.initState();
_futureAlbum = fetchAlbum();
}
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Update Data Example',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Scaffold(
appBar: AppBar(
title: const Text('GeeksForGeeks'),
backgroundColor: Colors.green,
),
body: Container(
alignment: Alignment.center,
padding: const EdgeInsets.all(8.0),
child: FutureBuilder<Album>(
future: _futureAlbum,
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.done) {
if (snapshot.hasData) {
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(snapshot.data!.title),
TextField(
controller: _controller,
decoration:
const InputDecoration(hintText: 'Enter Title'),
),
ElevatedButton(
child: const Text('Update Data'),
onPressed: () {
setState(() {
_futureAlbum = updateAlbum(_controller.text);
});
},
)
// RaisedButton is deprecated and should not be used.
// Use ElevatedButton instead.
// RaisedButton(
// child: const Text('Update Data'),
// onPressed: () {
// setState(() {
// _futureAlbum = updateAlbum(_controller.text);
// });
// },
// ),
],
);
} else if (snapshot.hasError) {
return Text("${snapshot.error}");
}
}
return const CircularProgressIndicator();
},
),
),
),
);
}
}
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