JSON Parsing in Android using Retrofit Library

JSON is also known as (JavaScript Object Notation) is a format to exchange the data from the server. The data stored in JSON format is lightweight and easy to handle. With the help of JSON, we can access the data in the form of JsonArray, JsonObject, and JsonStringer. In this article, we will specifically take a look at the implementation of JsonObject using the Retrofit library in Android.  

Note: To parse JSON object in android using Volley library please refer to JSON Parsing in Android using Volley Library

JSON Object: Json Object can be easily identified with “{” braces opening and “}” braces closing. We can fetch data from JSON objects with their key value. From that key, we can access the value of that key.  

What we are going to build in this article? 

We will be building a simple application in which we will be displaying a simple CardView in which we will display a single course that is available on Geeks for Geeks. A sample video is given below to get an idea about what we are going to do in this article. Note that we are going to implement this project using the Java language.  

Below is the JSON object from which we will be displaying the data in our Android App.  

{

 “courseName”:”Fork CPP”,

 “courseimg”:”https://media.geeksforgeeks.org/img-practice/banner/fork-cpp-thumbnail.png%E2%80%9D,

 “courseMode”:”Online Batch”,

 “courseTracks”:”6 Tracks”

}

Step by Step Implementation

Step 1: Create a New Project

To create a new project in Android Studio please refer to . Note that select Java as the programming language.

Step 2: Add the below dependency in your build.gradle file

Below is the dependency for Volley which we will be using to get the data from API. For adding this dependency navigate to the app > Gradle Scripts > build.gradle(app) and add the below dependency in the dependencies section. We have used the Picasso dependency for image loading from the URL.    

// below dependency for using retrofit.

implementation 'com.squareup.retrofit2:retrofit:2.9.0'

implementation 'com.squareup.retrofit2:converter-gson:2.5.0'

// below dependency for using picasso image loading library

implementation 'com.squareup.picasso:picasso:2.71828'

After adding this dependency sync your project and now move towards the AndroidManifest.xml part.  

Step 3: Adding permissions to the internet in the AndroidManifest.xml file

Navigate to the app > AndroidManifest.xml and add the below code to it. 

Step 4: Working with the activity_main.xml file

Navigate to the app > res > layout > activity_main.xml and add the below code to that file. Below is the code for the activity_main.xml file. 

Step 5: Creating a modal class for storing our data

Navigate to the app > java > your app's package name > Right-click on it > New > Java class and name it as RecyclerData and add the below code to it. Comments are added inside the code to understand the code in more detail.

Step 6: Creating an Interface class for our API Call

Navigate to the app > java > your app's package name > Right-click on it > New > Java class select it as Interface and name the file as RetrofitAPI and add below code to it. Comments are added inside the code to understand the code in more detail.

Step 7: Working with the MainActivity.java file

Go to the MainActivity.java file and refer to the following code. Below is the code for the MainActivity.java file. Comments are added inside the code to understand the code in more detail.

Now run your app and see the output of the app. 

Output: