Intenté estoenlaza y estoenlaza para construir un caché Retrofit sin conexión.

El problema es que si pongo el teléfono en modo Avión, el Response.body () siempre es nulo.

Aquí está mi código:

OkHttpClient client = new OkHttpClient
  .Builder()
  .cache(new Cache(App.sApp.getCacheDir(), 10 * 1024 * 1024)) // 10 MB
  .addInterceptor(new Interceptor() {
    @Override public Response intercept(Chain chain) throws IOException {
      Request request = chain.request();
      if (App.isNetworkAvailable()) {
        request = request.newBuilder().header("Cache-Control", "public, max-age=" + 60).build();
      } else {
        request = request.newBuilder().header("Cache-Control", "public, only-if-cached, max-stale=" + 60 * 60 * 24 * 7).build();
      }
      return chain.proceed(request);
    }
  })
  .build();

 retrofit = new retrofit2.Retrofit.Builder()
                    .baseUrl(BASE_URL)
                    .addConverterFactory(GsonConverterFactory.create())
                    .client(okHttpClient)
                    .build();

 final RetrofitServiceInterface service = RetrofitClient.getRetrofitInstance(this).create(RetrofitServiceInterface.class);
        Call<List<RetroPhoto>> call = service.getAllPhotos();
        call.enqueue(new Callback<List<RetroPhoto>>() {
            @Override
            public void onResponse(Call<List<RetroPhoto>> call, Response<List<RetroPhoto>> response) {

                generateDataList(response.body()); ////HERE!!!!
            }

            @Override
            public void onFailure(Call<List<RetroPhoto>> call, Throwable t) {
                Toast.makeText(MainActivity.this, "Something went wrong...Please try later!", Toast.LENGTH_SHORT).show();
            }
        });