Retrofit Android Sample

###Project Structure###

  Main Project
  ├── Api Lib
  │     ├── <some stuff from the lib>
  │     └── library
  │         ├── AndroidManifest.xml
  │         ├── res
  │         └── src // -> contains the Retrofit Java interfaces and Client, also information about our backend url
  │ 
  ├── Lib Commons
  │     └── <same structure as the lib 1>
  |         └──  // -> contains the app Models, simple POJOs for rest communication and not only
  │ 
  └── Sample App folder
        └── AndroidManifest.xml
        └── res
        └── src  // -> the sample app usage

###What is retrofit### Retrofit library is a type-safe REST client for Android and Java created by Square Open Source. With this library you can request the webservices of a REST api with POST, GET and more. This library is awesome and very useful, but you need a good architecture and a good practice to use it as best as possible. This sample might offer you just that.

###Why should I use it?### This part is the boring one. Often this is the part where you can read a big amount of theories and bechmarks on Retrofit, Volley, Asynctask… But that is not the purpose of this article. I want to show you how to use Retrofit in a smart way and not how to fell asleep quickly tonight ;) For those of you who were looking for an article about an alternative way to call a Rest API or why it’s forbidden to use Asynctask in your project, I advise you to read these articles, which are quite long but very interesting : This article about Retrofit and Volley and this article is about Asynctask. Now that you have read or skipped this part we can go further and see How to use Retrofit.

###How to use the sample?###

1 Inside your application you should create your SampleClient

       // this starts the client with the default values: logLevel NONE, linked to Production URL, app version 1.0
       client = RetrofitSampleClient.start();
       
       // if you want to customise the client and start it linked to Test environment you can do it so
       client = new RetrofitSampleClient.Builder().useTestServer().build();
       
       // other available methods
       .setLoggingLevel(RestAdapter.LogLevel.FULL) //-> NONE || BASIC || HEADERS || HEADERS_AND_ARGS
       .appVersion("0.0.3-debug")                  //-> is used for User-Agent Header 
       .useTestServer()                            //-> will use the QA URL from Api Constants
       ...

2 inside ApiConstants you can define your host URL

       public static final String PROD_URL = "https://api.sample.com/rest";
       public static final String TEST_URL = "http://qa.sample.com/rest";

• if you wish to send requests to a different host, you can change the endpoint by calling:

       RetrofitSampleApplication.getInstance().setEndpoint("http://jsonplaceholder.typicode.com");

• this will change the endpoint for all services, or if you wish to change the host for one service only:

       String url = "http://jsonplaceholder.typicode.com";
       SampleService sampleService = RetrofitSampleApplication.getInstance().getHostAdapter(url).create(SampleService.class);
       sampleService.doSomething();

3 Wherever you want to make a request you can do it like:

       RetrofitSampleApplication.getInstance().getXService().doSomething();

###Conclusion###

Now you have a great, sexy, powerful application with Retrofit. TA-DAH :D !