Volley never returns VolleyError or explains why there is an exception

Question

With the Volley libraries, I extended the Request object to implement GSON serialization. I then extended that new object for how I want to do some of my PUT requests. This is the first object for the GSON serialization:

@Override  
protected Response<t> parseNetworkResponse(NetworkResponse response) {  
    try {  
        String jsonString = new String(response.data, HttpHeaderParser.parseCharset(response.headers)); //response may be too large for string?
        t parsedGSON = mGson.fromJson(jsonString, cls);
        Response <t> returnMessage = Response.success(parsedGSON,  
                HttpHeaderParser.parseIgnoreCacheHeaders(response));
        return returnMessage;

    } catch (UnsupportedEncodingException e) { 
        e.printStackTrace();
        return Response.error(new ParseError(e));  
    } catch (JsonSyntaxException je) {
        je.printStackTrace();
        Log.e("GsonRequest", je.getMessage()!=null?je.getMessage():"JsonSyntaxError");
        return Response.error(new ParseError(je));  
    }  
}  

When my network response gets to Response <t> returnMessage = Response.success(parsedGSON, HttpHeaderParser.parseIgnoreCacheHeaders(response)); I have populated <t> objects with the correct classes I passed in completely serialized with all variables and no errors. Yet for some reason Volley jumps to } catch (JsonSyntaxException je) { and I can't reveal the contents of je with debugging breakpoints or printing logs. Also in my extended class:

 new ErrorListener() {
        @SuppressWarnings("unused")
        @Override
        public void onErrorResponse(VolleyError error) {
            error.printStackTrace();

The onErrorResponse is never called (neither is my onResponse section either)

So now I have no idea why Volley is catching a JSONException, when serialization was successful, and I have no idea why Volley isn't returning the Error objects

Insight appreciated

Answer 1

The answer is that any Volley function you extend or override must have

    @Override
protected void deliverResponse(T response) {
    // TODO Auto-generated method stub
    mListener.onResponse(response);
}

function implemented. The Listener must be initialized in the constructor and have the onResponse method implemented.

Otherwise your network call will never return in the onResponse section.

EDIT: and your extended Request class has to also implement deliverError, along with deliverResponse

private final Listener<T> mListener;
private ErrorListener mErrorListener;

@Override
 public void deliverError(VolleyError error) {
    mErrorListener.onErrorResponse(error);
}

with ErrorListener initialized in your constructor