java - AndroidでYahooの連絡先を取得する方法は?

Question

私はアンドロイドが初めてです。アプリケーションでヤフーの連絡先を取得するためのアプリを実装していますが、アプリケーションを正常に実行すると、ログインして同意をクリックして情報を共有しますが、これらのタイプのエラーに直面します-

Authentication error: Unable to respond to any of these challenges: 
{oauth=WWW-Authenticate: Oath oath_problem="signature_invalid", realm="yahooapis.com"} 

と

error while fetching user contact

誰でも私を助けることができますか？これが私のコードです：

---

   private void getAllContacts() throws UnsupportedEncodingException,ClientProtocolException, IOException 
   {
        HttpClient httpclient = new DefaultHttpClient();

        String host_url = "http://social.yahooapis.com/v1/user/" + mUSER_GUID+ "/contacts";

        String nonce = ""+System.currentTimeMillis();
        String timeStamp = ""+(System.currentTimeMillis()/1000L);

        try{
            String params = 
                    ""+encode("oauth_consumer_key")+"=" + encode(CONSUMER_KEY)
                    + "&"+encode("oauth_nonce")+"="+encode(nonce)
                    + "&"+encode("oauth_signature_method")+"="+encode("HMAC-SHA1")
                    + "&"+encode("oauth_timestamp")+"="+encode(timeStamp)
                    + "&"+encode("oauth_token")+"="+ACCESS_TOKEN
                    + "&"+encode("oauth_version")+"="+encode("1.0")

                    ;
            String baseString = encode("GET")+"&"+encode(host_url)+"&"+encode(params);
            String signingKey = encode(CONSUMER_SECRET)+"&"+encode(ACCESS_TOKEN_SECRET);
            Log.e(TAG, "base string: " + baseString);
            String lSignature = computeHmac(baseString, signingKey);
            Log.e(TAG, "signature: " + lSignature);
            lSignature = encode(lSignature);
            Log.e(TAG, "signature enacoded: " + lSignature);

            String lRequestUrl = host_url
                                + "?oauth_consumer_key="+CONSUMER_KEY
                                + "&oauth_nonce="+nonce
                                + "&oauth_signature_method=HMAC-SHA1"
                                + "&oauth_timestamp="+timeStamp
                                + "&oauth_token="+ACCESS_TOKEN
                                + "&oauth_version=1.0"
                                + "&oauth_signature="+lSignature
                                ;
            Log.e(TAG, lRequestUrl);



            HttpGet httpget = new HttpGet(lRequestUrl);
            ResponseHandler<String> responseHandler = new BasicResponseHandler();
            responseBody = httpclient.execute(httpget, responseHandler);
            Log.e(TAG, "contacts response: " + responseBody);


            String strUrl=responseBody;
            DefaultHttpClient httpClient=new DefaultHttpClient();
            HttpPost httppost=new HttpPost(strUrl);
            HttpResponse httpresponse=httpClient.execute(httppost);
            HttpEntity httpEntity=httpresponse.getEntity();

            String strXml=EntityUtils.toString(httpEntity);

            ArrayList<HashMap<String , String>> arrayList=new ArrayList<HashMap<String,String>>();

            XMLParser xmlparser=new XMLParser();
            String strxml = xmlparser.getXmlFromUrl(responseBody); 
            Log.e("",""+strxml); // getting xml url here
            Document doc  = xmlparser.getDomElement(strxml);        // getting data object model
            NodeList nl   = doc.getElementsByTagName(KEY_FIELD);    // Looping through all item nodes <field>

            for(int i=0 ; i<nl.getLength() ; i++ )
            {
                //creating new hash map
                HashMap<String ,String > map = new HashMap<String, String>();
                Element e = (Element) nl.item(i);

                //Adding each child node to HashMap Key Value pair
                map.put(KEY_ID      , xmlparser.getValue(e,    KEY_ID));
                map.put(KEY_TYPE    , xmlparser.getValue(e,  KEY_TYPE));
                map.put(KAE_VALUE   , xmlparser.getValue(e, KAE_VALUE));

                Log.e("Hash Map","Key Value"+map);

                //Adding hashlist to arrayList
                arrayList.add(map);
                Log.e("ArrayList ","of Contact "+arrayList);
            }



        }

        catch(Exception e)
        {
            e.printStackTrace();
            Log.e(TAG, "error while fetching user contacts");
        }


    }

前もって感謝します。