Overview

Retrofit is a type-safe REST client for Android built by Square. The library provides a powerful framework for authenticating and interacting with APIs and sending network requests with OkHttp.

This library makes downloading JSON or XML data from a web API fairly straightforward. Once the data is downloaded then it is parsed into a Plain Old Java Object (POJO) which must be defined for each “resource” in the response.

Setup

Make sure to require Internet permissions in your AndroidManifest.xml file:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    <uses-permission android:name="android.permission.INTERNET" />
    .
    .
    .
</manifest>

Add the following to your app/build.gradle file:

dependencies {
  compile 'com.squareup.okhttp:okhttp:2.4.0'
  compile 'com.squareup.retrofit:retrofit:1.9.0'
  compile 'com.google.code.gson:gson:2.3'
}