Android : Android Web View not intercepting duplicate calls

I have overriden shouldInterceptRequest(WebView view, String url) of WebViewClient to add my custom header because shouldOvverideURL() was not working for the resource loads like images, videos of my web content.

I am returning my own response for the resources.Below is the code

@Override
    public WebResourceResponse shouldInterceptRequest(WebView view, String url)
    {
        // TODO Auto-generated method stub
        DefaultHttpClient client = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(url);
        httpGet.setHeader(SLCFileUtility.TOKEN_HTTP_RESPONSE_HEADER, SLCFileUtility.getToken());
        HttpResponse httpReponse = null;
        try {
            httpReponse = client.execute(httpGet);
        }
        catch (ClientProtocolException e) {
            e.printStackTrace();
        }
        catch (IOException e) {
            e.printStackTrace();
        }

        // here omit getting content-type and encoding
        try {
            InputStream reponseInputStream = httpReponse.getEntity().getContent();

            String encoding = null;
            String contentType = null;
            if (httpReponse.getEntity().getContentEncoding() != null) {
                encoding = httpReponse.getEntity().getContentEncoding().getValue();
            }
            if (httpReponse.getEntity().getContentType() != null) {
                contentType = httpReponse.getEntity().getContentType().getValue();
                if (contentType.equals("text/html") || contentType.equals("application/javascript")) {
                    logger.info("response is not required for " + httpReponse.toString() + " for the url" + url);
                    view.clearCache(true);
                    return null;
                }
                else {
                    logger.info("the token in header"
                                + httpGet.getHeaders(SLCFileUtility.TOKEN_HTTP_RESPONSE_HEADER)[0].getValue());
                    logger.info("response " + httpReponse.toString() + " for the url" + url);
                    view.clearCache(true);
                    return new WebResourceResponse(contentType, encoding, reponseInputStream);
                }
            }
            else { // for .server files
                logger.info("the token in header"
                            + httpGet.getHeaders(SLCFileUtility.TOKEN_HTTP_RESPONSE_HEADER)[0].getValue());
                logger.info("response " + httpReponse.toString() + " for the url without content type" + url);
                view.clearCache(true);
                return new WebResourceResponse(contentType, encoding, reponseInputStream);
            }

        }
        catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        view.clearCache(true);

But when the request is being sent again for the same resource like a video, the method shouldInterceptRequest() is not called. I learnt from here that web view caches the requests from here Intercept and override HTTP-requests from WebView

So i am calling web view clearCache(true) everytime before i leave shouldInterceptRequest(). But still its not working and am not able to add my custom header "token".

cheers, Saurav