I am using Google Volley on the Android platform.
I am having a problem in which the error parameter in onErrorResponse is returning a null n
It turns out that it is impossible to guarantee that error.networkResponse is non-null without modifying Google Volley code because of a bug in Volley that throws the Exception NoConnectionError for Http Status Code 401 (HttpStatus.SC_UNAUTHORIZED) in BasicNetwork.java (134) prior to setting the value of networkResponse.
Instead of fixing the Volley code, our solution in this case was to modify the Web Service API to send Http Error Code 403 (HttpStatus.SC_FORBIDDEN) for the particular case in question.
For this Http Status Code, the value of error.networkResponse is non-null in the Volley error handler: public void onErrorResponse(VolleyError error). And, error.networkResponse.httpStatusCode correctly returns HttpStatus.SC_FORBIDDEN.
Rperryng's suggestion of extending the Request class may have provided a solution, and is a creative and excellent idea. Thank you very much for the detailed example. I found the optimal solution for our case is to use the work-around because we are fortunate enough to have control of the web services API.
I might opt for fixing the Volley code in one location within BasicNetwork.java if I did not have access to making a simple change at the server.