Http Status Code in Android Volley when error.networkResponse is null

Question

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

Answer 1

Or, how can I ensure error.networkResponse is non-null in onErrorResponse?

My first thought would be to check if the object is null.

@Override
public void onErrorResponse(VolleyError error) {
    NetworkResponse networkResponse = error.networkResponse;
    if (networkResponse != null && networkResponse.statusCode == HttpStatus.SC_UNAUTHORIZED) {
        // HTTP Status Code: 401 Unauthorized
    }
}

Alternatively, you could also try grabbing the Status Code by extending the Request class and overriding parseNetworkResponse.

For example, if extending the abstract Request class

public class GsonRequest extends Request {

    ...
    private int mStatusCode;

    public int getStatusCode() {
        return mStatusCode;
    }
    ...

    @Override
    protected Response parseNetworkResponse(NetworkResponse response) {

        mStatusCode = response.statusCode;
        try {
            Log.d(TAG, "[raw json]: " + (new String(response.data)));
            Gson gson = new Gson();
            String json = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
            return Response.success(gson.fromJson(json, mClazz),
                HttpHeaderParser.parseCacheHeaders(response));

        } catch (UnsupportedEncodingException e) {
            return Response.error(new ParseError(e));
        } catch (JsonSyntaxException e) {
            return Response.error(new ParseError(e));
        }
    }
    ...
}

Or, if you are using one of the toolbox classes that already extend the abstract Request class and you don't want to muddle up the implementation for parseNetworkResponse(NetworkResponse networkResponse), continue overriding the method but return the super's implementation via super.parseNetworkResponse(networkResponse)

e.g. StringResponse

public class MyStringRequest extends StringRequest {

    private int mStatusCode;

    public MyStringRequest(int method, String url, Listener listener,
            ErrorListener errorListener) {
        super(method, url, listener, errorListener);
    }

    public int getStatusCode() {
        return mStatusCode;
    }

    @Override
    protected Response parseNetworkResponse(NetworkResponse response) {
        mStatusCode = response.statusCode;
        return super.parseNetworkResponse(response);
    }
}

usage:

public class myClazz extends FragmentActivity {


    private Request mMyRequest;
    ...

    public void makeNetworkCall() {
    mMyRequest = new MyNetworkRequest(
            Method.GET, 
            BASE_URL + Endpoint.USER,
            new Listener() {

                @Override
                public void onResponse(String response) {
                    // Success

                }
            }, 
            new ErrorListener() {

                @Override
                public void onErrorResponse(VolleyError error) {
                    if (mMyRequest.getStatusCode() == 401) {
                        // HTTP Status Code: 401 Unauthorized
                    }
                }
            });

    MyVolley.getRequestQueue().add(request);
}

Of course, the option to override the method inline is available too

public class MyClazz extends FragmentActivity {

    private int mStatusCode;

    ...

    public void makeNetworkCall() {

        StringRequest request = new StringRequest(
                Method.GET, 
                BASE_URL + Endpoint.USER,
                new Listener() {

                    @Override
                    public void onResponse(String response) {
                        // Success

                    }
                }, 
                new ErrorListener() {

                    @Override
                    public void onErrorResponse(VolleyError error) {
                        if (mStatusCode == 401) {
                            // HTTP Status Code: 401 Unauthorized
                        }
                    }
                }) {

                    @Override
                    protected Response parseNetworkResponse(NetworkResponse response) {
                        mStatusCode = response.statusCode;
                        return super.parseNetworkResponse(response);
                    }
                };
    MyVolley.getRequestQueue.add(request);
}

Update:
HttpStatus is Deprecated. Use HttpURLConnection instead. See Link.