Flutter - Updating Data on the Internet

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:

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

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Use the http.put() method to update the title of the Album in JSONPlaceholder as shown below:

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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:

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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.

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Now use the fetch() method to fetch the data as shown below:

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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:

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Use the FlutterBuilder widget to display the data on the screen as shown below:

Complete Source Code:

Output: