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Flutter - Updating Data on the Internet

Last Updated : 15 Jul, 2025
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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>:

  1. Use the dart:convert package to convert the response body into a JSON Map.
  2. Use the fromJSON() factory method to convert JSON Map into Album if the server returns an OK response with a status code of 200.
  3. 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();
            },
          ),
        ),
      ),
    );
  }
}


Output:


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Flutter - Fetching Data From the Internet

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