oauth_oncreate.java

btnLogin = (Button) findViewById(R.id.btnLogin);
btnLogin.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
    try {
        	String authURL = provider.retrieveRequestToken(
								consumer, CALLBACK_URL);

		Log.d("OAuthTwitter", authURL);
		startActivity(new Intent(Intent.ACTION_VIEW, Uri
								.parse(authURL)));
    } catch (OAuthMessageSignerException e) {
	e.printStackTrace();
    } catch (OAuthNotAuthorizedException e) {
	e.printStackTrace();
    } catch (OAuthExpectationFailedException e) {
	e.printStackTrace();
    } catch (OAuthCommunicationException e) {
	e.printStackTrace();
    }
  }
});