Why I chose Retrofit ?

Before using Retrofit from square, I tried volley (from Google) and AsyncTask. After using retrofit,my works gets more easy.You must read the below topics before jumping into this Tutorial.This is a beginner based project which gives an idea of retrieving from api using Retrofit.

This project is also added to my Github

Comparison  of AsyncHttp ,Volley and Retrofit

Volley is a small library compared to Retrofit ,but it is undocumented. Retrofit is developed by Square,also famous for okhttp,picasso..etc(you can find it from here).If you need volley ,then you can from Google Training  or Volley Plus from DWork.

UPDATE: Proceed to Next Retrofit Section,How to load image api using Retrofit

UPDATE2: Flip Like Flipboard using Retrofit, How to create Flipboard using Retrofit

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 Introduction

Retrofit is a REST Client for Android and Java by Square.This library is easy learn and has more features.This is beginner friendly compared to other Networking libraries.You can GET,POST,PUT,DELETE  ..etc using this library. You can also use picasso for image loading.Read this before using Picasso or Volley.

Get rid of the Introduction and Lets star the Coding !!!

We are using Github Api for this App : https://api.github.com/users/basil2style

You can search github users details using this demo app

GITHUB

Download APK :

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1) Overview

In Retrofit,we need to create 3 classes.

1) POJO (Plain Old Java Object) or Model Class – The json retrieved from the server is added to this class.

2) Interface : Now we need to create an interface for managing url calls like GET,POST..etc.This is the service class.

3) RestAdapter Class : This is RestClient Class. Gson is used in default for the retrofit.You can use setup your own converter for this purpose like jackson which will describe on later tutorials.

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2) Adding Retrofit Library to Project

For Gradle :

compile 'com.squareup.retrofit:retrofit:1.9.0'

Currently,1.9.0 is the latest version.You can get updated version from here

For JAR :

          Download jar

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3) Create Android Project

1) Creating New Project in Android Studio is by : File  =>  New Project and fill the descriptions and click Next.

2) Fill the minimum SDK for the project, i use 4.0+ (Retrofit  requires Android 2.3+ or Java 6)

3) Select Blank Activity and then fill out the details Activity Name and Layout Name then click Finish.

4) For Gradle : You can add Retrofit library by adding it on app =>build.gradle (in project view).

For Jar : Add jar to app => libs folder and right click on the jar file and click on Add as Library.

5) Also create two packages as API and model.

6) Right Click on API and Click New => Java Class ,then  Name it as gitapi and Kind as Interface.

7) Right Click on Package model and Click New => Java Class,then Name it as gitmodel and Kind as Class

 

4) Android Manifest 

1) Add INTERNET PERMISSION

Your Manifest will look like :

5) Model Class

First,we need to create POJO or Model class.The Json from server cannot be use directly in Java,so we need to use model class.

For URL structure look like this : https://api.github.com/users/ + “search term”

For eg :   https://api.github.com/users/basil2style

Our Json Response look like this :

This is a JSON Object. If you don’t  know the difference between Json Array and Json Object,please read this

Use jsonschema2pojo for creating the pojo easily.Do not use this for every other Json requests,sometime it gives error. I use Source type as Json and Annotation style as Gson,then click on preview.

gitmodel.java : http://pastebin.com/4xckerN1

6) gitapi.java

1) Now we need url calling using our interface.

(“/users/{user}”),this will call the server.where url is from after the BASE URL.The service  calling url will start with ‘/’ and {user} is the string retrieved from edittext.

(“user”) String user is the string which we get from the edit text.

response from the server is then saved into the Pojo.

  7) RestAdapter

Now,this is the main part.you need to setup the Rest Adapter and the service.

1)  API is the Base URL.

2) We need to create a RestAdapter object with Endpoint(API) and then buid().

3) Create a service for adapter with our gitapi.

4) Call the function for getting the response,Callback is used for async method.We need Callback for both success request and error handling.

5) Our parsed json will be now in POJO. You can call each by calling each item.

 String API = "https://api.github.com";

RestAdapter restAdapter = new RestAdapter.Builder().setLogLevel(RestAdapter.LogLevel.FULL)setEndpoint(API).build(); 
 
 gitapi git = restAdapter.create(gitapi.class);

git.getFeed(user,new Callback() {
 
 public void success(gitmodel gitmodel, Response response) {
tv.setText("Github Name :"+gitmodel.getName()+

"\nWebsite :"+gitmodel.getBlog()+"\nCompany Name :"+gitmodel.getCompany());
pbar.setVisibility(View.INVISIBLE); //disable progressbar
 }

public void failure(RetrofitError error) {
 tv.setText(error.getMessage());
 pbar.setVisibility(View.INVISIBLE); //disable progressbar
 }
 });

Full MainActivty.java Code

UPDATE: Proceed to Next Retrofit Section,How to load image api using Retrofit