gistfile1.java

public class PhotographersViewModel extends ViewModel {


    //this is the data that we will fetch asynchronously
    private MutableLiveData<List<Photographer>> photographerList;


    //we will call this method to get the data
    public LiveData<List<Photographer>> getPhotographer() {
//if the list is null
        if (photographerList == null) {
            photographerList = new MutableLiveData<List<Photographer>>();
//we will load it asynchronously from server in this method
            loadPhotographers();
        }
//finally we will return the list
        return photographerList;
    }

    //This method is using Retrofit to get the JSON data from URL
    private void loadPhotographers() {
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(Api.BASE_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .build();

        Api api = retrofit.create(Api.class);
        Call<List<Photographer>> call = api.getPhotographer();
        call.enqueue(new Callback<List<Photographer>>() {
            @Override
            public void onResponse(Call<List<Photographer>> call, Response<List<Photographer>> response) {
//finally we are setting the list to our MutableLiveData
                photographerList.setValue(response.body());
            }

            @Override
            public void onFailure(Call<List<Photographer>> call, Throwable t) {
            }
        });
    }