How can I debug my retrofit API call?

Question

I'm using retrofit to get some data from the Flickr api. The method I'm making the call in looks like this:

public static List<String> getImageIds(int size) {
    Call<PhotosList> call = flickrService.getPhotos(apiKey, format, "1");
    Log.d("TEMP_TAG", "photo url: " + call.request().url().toString());
    photoIds = new ArrayList<String>();

    call.enqueue(new Callback<PhotosList>(){
        @Override
        public void onResponse(Call<PhotosList> call, Response<PhotosList> response) {
            Log.d("TEMP_TAG", "it's getting here");
            PhotosList photosList = response.body();
            List<Photo> photos = photosList.getPhotos().getPhoto();

            for(Photo photo : photos) {
                Log.d("TEMP_TAG", "adding photo id to list: " + photo.getId());
                photoIds.add(photo.getId());
            }
        }

        @Override
        public void onFailure(Call<PhotosList> call, Throwable t) {
            // TODO: Clean up
            Log.d("TEMP_TAG", "photoId: ");
        }
    });
    Log.d("TEMP_TAG", "it's getting here too");
    return photoIds;
}

However it is never getting into the onResponse() method. The first log statement within onResponse() never prints, neither does the log statement in onFailure(). When I try entering the URL that is returned by call.request().url().toString() in the browser it works fine, and I get the expected JSON. Why is my enqueue() method never firing?

Thanks for any help!

Answer 1

Use HttpLoggingInterceptor along with Retrofit.

If this helps, add this inside your build.gradle -

//Retrofit and OkHttp for Networking
implementation 'com.squareup.retrofit2:retrofit:2.7.1'
implementation 'com.squareup.retrofit2:converter-gson:2.7.1'
//Logging Network Calls
implementation 'com.squareup.okhttp3:logging-interceptor:4.2.1'

Inside your APIClient class add this -

public class ApiClient {
    private static Retrofit retrofit = null;

    public static Retrofit getClient(){

        HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();
        interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
        OkHttpClient client = new OkHttpClient.Builder()
                .addInterceptor(interceptor)
                .build();


        if(retrofit==null){
            retrofit = new Retrofit.Builder()
                    .baseUrl(BuildConfig.baseUrl)
                    .addConverterFactory(GsonConverterFactory.create())
                    .client(client)
                    .build();
        }
        return retrofit;
    }
}

Kotlin Code

val interceptor : HttpLoggingInterceptor = HttpLoggingInterceptor().apply {
            this.level = HttpLoggingInterceptor.Level.BODY
        }

val client : OkHttpClient = OkHttpClient.Builder().apply {
            this.addInterceptor(interceptor)
        }.build()


fun getService(): Service {
        return Retrofit.Builder()
                .baseUrl(BASE_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(LiveDataCallAdapterFactory())
                .client(client)
                .build()
                .create(Service::class.java)
    }

And you will be able to log the Retrofit Network calls that you make.

Let me know if you need more information.