Android - Retrofit：从.enqueue直接跳到结尾，onResponse永远不会被调用

Question

我正在尝试创建一个Retrofit函数来检索一个对象列表，但它不起作用。它从“getAnuncios.enqueue”直接跳到结尾，从不调用onResponse。 我记录了http活动，没关系（200），但我不知道为什么从不调用onResponse。

以下是代码：

package com.sa.santaajuda.fragments;

import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import com.sa.santaajuda.R;
import com.sa.santaajuda.activities.LoginActivity;
import com.sa.santaajuda.activities.MainActivityCliente;
import com.sa.santaajuda.adapters.AnuncioServicoAdapter;
import com.sa.santaajuda.beans.AnuncioServico;
import com.sa.santaajuda.beans.Usuario;
import com.sa.santaajuda.services.AnuncioServicoService;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;

import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.logging.HttpLoggingInterceptor;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

/**
 * Created by b1104586 on 12/09/2017.
 */

public class BuscarServicos  extends Fragment {
    private RecyclerView mRecycleView;
    private ArrayList<AnuncioServico> listaAnuncios;
    public BuscarServicos(){}



    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        View view = inflater.inflate(R.layout.activity_buscar_servicos, container, false);
        mRecycleView =  view.findViewById(R.id.recycler_anuncios_servico);
        getAnunciosServico();

        RecyclerView.LayoutManager layout = new LinearLayoutManager(getContext(),LinearLayoutManager.VERTICAL, false);

        mRecycleView.setLayoutManager(layout);
        return(view);
    }

    public void getAnunciosServico(){
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();

        // set your desired log level
        logging.setLevel((HttpLoggingInterceptor.Level.BODY));

        OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
        // add your other interceptors …

        // add logging as last interceptor
        httpClient.addInterceptor(logging);  // <-- this is the important line!

        //Instância o serviço que irá comunicar para obter os anuncios de serviço
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(AnuncioServicoService.BASE_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .client(httpClient.build())
                .build();

        AnuncioServicoService service = retrofit.create(AnuncioServicoService.class);

        Call<List<AnuncioServico>> getAnuncios = service.listarAnuncios();

        getAnuncios.enqueue(new Callback<List<AnuncioServico>>() {

            @Override
            public void onResponse(Call<List<AnuncioServico>> callback, Response<List<AnuncioServico>> response) {
                if (response.isSuccessful()) {
                    //limpa a lista local
                    listaAnuncios.clear();
                    List<AnuncioServico> listaTemp = response.body();
                    listaAnuncios.addAll(listaTemp);
                    mRecycleView.setAdapter(new AnuncioServicoAdapter(listaAnuncios, getContext()));
                    if (listaAnuncios.isEmpty())
                        Toast.makeText(getContext(), "Nenhum anúncio de serviço para exibir!", Toast.LENGTH_SHORT).show();
                }else{
                    System.out.println(response.body());
                }
            }

            @Override
            public void onFailure(Call<List<AnuncioServico>> call, Throwable t) {
                Toast.makeText(getContext(), "Erro ao comunicar com o servidor!", Toast.LENGTH_SHORT).show();
                t.printStackTrace();
            }
        });
    }
    @Override
    public  void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
    }
}