RetrofitModule.java

package com.arellomobile.mvp.sample.github.di.modules;

import java.lang.reflect.Field;

import com.google.gson.FieldNamingPolicy;
import com.google.gson.FieldNamingStrategy;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

import javax.inject.Singleton;

import dagger.Module;
import dagger.Provides;
import retrofit2.Converter;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;
import rx.schedulers.Schedulers;

/**
 * Date: 8/26/2016
 * Time: 12:28
 *
 * @author Artur Artikov
 */
@Module
public class RetrofitModule {
	@Provides
	@Singleton
	public Retrofit provideRetrofit(Retrofit.Builder builder) {
		return builder.baseUrl("https://api.github.com").build();
	}

	@Provides
	@Singleton
	public Retrofit.Builder provideRetrofitBuilder(Converter.Factory converterFactory) {
		return new Retrofit.Builder()
				.addCallAdapterFactory(RxJavaCallAdapterFactory.createWithScheduler(Schedulers.io()))
				.addConverterFactory(converterFactory);
	}

	@Provides
	@Singleton
	public Converter.Factory provideConverterFactory(Gson gson) {
		return GsonConverterFactory.create(gson);
	}

	@Provides
	@Singleton
	Gson provideGson() {
		return new GsonBuilder()
				.setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
				.setFieldNamingStrategy(new CustomFieldNamingPolicy())
				.setPrettyPrinting()
				.setDateFormat("yyyy-MM-dd'T'HH:mm:ssZ")
				.serializeNulls()
				.create();
	}

	private static class CustomFieldNamingPolicy implements FieldNamingStrategy {
		@Override
		public String translateName(Field field) {
			String name = FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES.translateName(field);
			name = name.substring(2, name.length()).toLowerCase();
			return name;
		}
	}
}