Android Google Oauth2 ContactService

Question

I am trying to implement Oauth2 for google services in my Android app. I need to obtain a user's email address. Currently I can obtain the access token and token secret, but when I try to use these to obtain the user's email address from the contactservice, I get the following error:

Caused by: java.lang.NullPointerException
    at com.google.gdata.client.authn.oauth.OAuthUtil.normalizeParameters(OAuthUtil.java:163)
    at com.google.gdata.client.authn.oauth.OAuthUtil.getSignatureBaseString(OAuthUtil.java:81)
    at com.google.gdata.client.authn.oauth.TwoLeggedOAuthHelper.addCommonRequestParameters(TwoLeggedOAuthHelper.java:79)
    at com.google.gdata.client.authn.oauth.TwoLeggedOAuthHelper.addParametersAndRetrieveHeader(TwoLeggedOAuthHelper.java:121)
    at com.google.gdata.client.authn.oauth.TwoLeggedOAuthHelper.getAuthorizationHeader(TwoLeggedOAuthHelper.java:112)
    at com.google.gdata.client.GoogleAuthTokenFactory$OAuthToken.getAuthorizationHeader(GoogleAuthTokenFactory.java:204)
    at com.google.gdata.client.http.HttpGDataRequest.<init>(HttpGDataRequest.java:331)
    at com.google.gdata.client.http.GoogleGDataRequest.<init>(GoogleGDataRequest.java:456)
    at com.google.gdata.client.http.GoogleGDataRequest$Factory.createRequest(GoogleGDataRequest.java:93)
    at com.google.gdata.client.http.HttpGDataRequest$Factory.getRequest(HttpGDataRequest.java:165)
    at com.google.gdata.client.Service.createRequest(Service.java:760)
    at com.google.gdata.client.GoogleService.createRequest(GoogleService.java:525)
    at com.google.gdata.client.Service.createFeedRequest(Service.java:1156)
    at com.google.gdata.client.Service.getFeed(Service.java:997)
    at com.google.gdata.client.GoogleService.getFeed(GoogleService.java:631)
    at com.google.gdata.client.Service.getFeed(Service.java:1017)
    at com.example.GmailOauthActivity$GmailEmailAddressTask.doInBackground(GmailOauthActivity.java:239)
    at com.example.GmailOauthActivity$GmailEmailAddressTask.doInBackground(GmailOauthActivity.java:220)
    at android.os.AsyncTask$2.call(AsyncTask.java:287)
    at java.util.concurrent.FutureTask.run(FutureTask.java:234)
    ... 4 more

Here is my code for obtaining the email address. If there is a simpler method, then that would be great too. Thanks :).

GoogleOAuthParameters oauthParameters = new GoogleOAuthParameters();
            oauthParameters.setOAuthConsumerKey(CONSUMER_KEY);
            oauthParameters.setOAuthConsumerSecret(consumer.getTokenSecret());
            oauthParameters.setScope(SCOPE);
            oauthParameters.setOAuthVerifier(verifier);
            oauthParameters.setOAuthToken(consumer.getToken());
            oauthParameters.setOAuthTokenSecret(consumer.getTokenSecret());
            ContactsService client=new ContactsService ("Service");
            client.setOAuthCredentials(oauthParameters, new OAuthHmacSha1Signer());
            oauthParameters.setOAuthType(OAuthParameters.OAuthType.TWO_LEGGED_OAUTH);
            client.setHeader("Authorization", "Bearer " + consumer.getToken());
            URL feedUrl = new URL("https://www.google.com/m8/feeds/contacts/default/full");
            com.google.gdata.client.Query myQuery = new com.google.gdata.client.Query(feedUrl);
            myQuery.setStartIndex(1);
            myQuery.setMaxResults(1);
            ContactFeed resultFeed = client.getFeed(feedUrl, ContactFeed.class);
            return resultFeed.getAuthors().get(0).getEmail();

Answer 1

I believe that the issue I was having was with forgetting to include certain items like "nonce" and "timestamp" in my GET query to the ContactService. I found a working solution online at http://androidwarzone.blogspot.com/2011/07/android-oauth-full-example-with-source.html . Hope this can help someone in the future.

Answer 2

Before you using any of the properties of oauthParameters ... check in an if condition if it is null .

Especially before this statement:

client.setOAuthCredentials(oauthParameters, new OAuthHmacSha1Signer());

and check if client is null for this:

ContactFeed resultFeed = client.getFeed(feedUrl, ContactFeed.class);