java.lang.NoClassDefFoundError: oauth.signpost.commonshttp.CommonsHttpOAuthConsumer android

Am using twitter integration using SocialLib project. But the thing is constantly am getting

java.lang.NoClassDefFoundError: oauth.signpost.commonshttp.CommonsHttpOAuthConsumer 

at the line

httpOauthConsumer = new CommonsHttpOAuthConsumer(consumerKey, consumerSec开发者_运维技巧ret);

and my imports are:

import oauth.signpost.commonshttp.CommonsHttpOAuthConsumer;
import oauth.signpost.commonshttp.CommonsHttpOAuthProvider;
import oauth.signpost.exception.OAuthCommunicationException;
import oauth.signpost.exception.OAuthExpectationFailedException;
import oauth.signpost.exception.OAuthMessageSignerException;
import oauth.signpost.exception.OAuthNotAuthorizedException;

and the jars i used and downloaded from:http://code.google.com/p/oauth-signpost/downloads/list

How to reslove this?

Hanks

---

Here is jarlibrary: http://code.google.com/p/oauth-signpost/downloads/detail?name=signpost-commonshttp4-1.2.1.1.jar&can=2&q= You should add it to your project as a external jar.