Retrofit Introduction

build.groovy

android {
  //...
}

dependencies {
    //...
    compile 'com.squareup.retrofit:retrofit:2.0.0-beta2'
    compile 'com.squareup.retrofit:converter-gson:2.0.0-beta2'
}

DataWebService.java

import retrofit.Call;
import retrofit.http.GET;

/**
 * Copyright (C) 2016 Mikhael LOPEZ
 * Licensed under the Apache License Version 2.0
 * Example Data WebService
 * Created by Mikhael LOPEZ on 18/12/2015.
 */
public interface DataWebService {

    @GET("data.json")
    Call<YourDTO> getData();
}

MainActivity.java

import retrofit.Call;
import retrofit.Response;

/**
 * Copyright (C) 2016 Mikhael LOPEZ
 * Licensed under the Apache License Version 2.0
 */
public class MainActivity extends Activity {
  //...
  
   private void downloadData() {
        DataWebService service = RetrofitFactory.getRetrofit().create(DataWebService.class);
        Call<DataDTO> call = service.getData();

        call.enqueue(new retrofit.Callback<DataDTO>() {
            @Override
            public void onResponse(Response<DataDTO> response) {
                if (response != null && response.isSuccess()) {
                    DataDTO data = response.body();
                    if (data != null) {
                        // TODO Work Well
                    } else {
                        // TODO Fail
                    }
                } else {
                    // TODO Fail
                }
            }

            @Override
            public void onFailure(Throwable t) {
                // TODO Fail
            }
        });
    }
}

retrofit-intro.md

Retrofit Introduction

Type-safe HTTP client for Android and Java by Square, Inc.

Download

Gradle:

compile 'com.squareup.retrofit:retrofit:2.0.0-beta2'

And Gson:

compile 'com.squareup.retrofit:converter-gson:2.0.0-beta2'

RetrofitFactory.java

import android.Manifest;
import android.support.annotation.RequiresPermission;

import retrofit.GsonConverterFactory;
import retrofit.Retrofit;

/**
 * Copyright (C) 2016 Mikhael LOPEZ
 * Licensed under the Apache License Version 2.0
 * RetrofitFactory to generate a Retrofit instance
 */
public class RetrofitFactory {
    // Base URL: always ends with /
    private static final String URL_MAIN_WEBSERVICE = "http://url-main-webservice/";

    //region Singleton Retrofit
    private static Retrofit retrofit;

    /**
     * Get {@link Retrofit} instance.
     * @return instances of {@link Retrofit}
     */
    @RequiresPermission(Manifest.permission.INTERNET)
    public static Retrofit getRetrofit() {
        if (retrofit == null) {
            retrofit = new Retrofit.Builder()
                    .baseUrl(URL_MAIN_WEBSERVICE)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
        }
        return retrofit;
    }
    //endregion
}