MainActivity.java

package com.example.aliso.sd.activity;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Toast;


import android.view.Menu;
import android.view.MenuItem;

import com.example.aliso.sd.R;


import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;


public class MainActivity extends AppCompatActivity implements Callback<ResponsePost> {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toast.makeText(getApplicationContext(), "Da", Toast.LENGTH_LONG).show();

        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(NetworkInterfaces.URL)
                .addConverterFactory(GsonConverterFactory.create())
                .build();
        //RequestPost requestPost = new RequestPost("8448507");

        NetworkInterfaces interfaces = retrofit.create(NetworkInterfaces.class);


        Call<ResponsePost> responseCall = interfaces.hacerLlamada();
        responseCall.enqueue(this);
        Toast.makeText(getApplicationContext(), "FIN  DA ", Toast.LENGTH_LONG).show();

    }

    @Override
    public void onResponse(Call<ResponsePost> call, Response<ResponsePost> response)
    {
        ResponsePost responsePost = response.body();
        System.out.println(" "  + responsePost.getCorreo()+ " ");
        Toast.makeText(getApplicationContext(),responsePost.getCelular()  , Toast.LENGTH_LONG).show();
    }


    @Override
    public void onFailure(Call<ResponsePost> call, Throwable t)
    {
        int x = 0;
        x++;
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }



    @Override
    public void onStart() {
        super.onStart();
    }

    @Override
    public void onStop() {
        super.onStop();
    }

}