Android：Google Data API - 401令牌无效错误

Account name = xxxxxx@gmail.com
Token is : DQAAALIAAAAh-xxxxxxx
Starting Google DATA API loader-----------------
Inside Google Notebook loader-----------------
Setting Token : DQAAALIAAAAh-xxxxx
Url is : https://docs.google.com/feeds/default/private/full
Exception getting docs feed : 401 Token invalid
Done Google DATA API loader-----------------

Log.d("Main","tInside GoogleDATA API -----------------");
    HttpTransport transport = new NetHttpTransport();
    GoogleHeaders headers = new GoogleHeaders();
    Log.d("Main","tSetting Token : " + authToken);
    headers.setGoogleLogin(authToken);
    headers.gdataVersion="3.0";
    transport.defaultHeaders = headers;
    AtomParser parser = new AtomParser();
    parser.namespaceDictionary = Namespace.DICTIONARY;
    transport.addParser(parser);
    try {
        DocsUrl url = DocsUrl.forDefaultPrivateFull();
        DocumentListFeed feed = DocumentListFeed.executeGet(transport,url);
        List<DocumentListEntry> docs = feed.docs;
        Log.d("Main","tDocs count = " + docs.size());
        for (Iterator iterator = docs.iterator(); iterator.hasNext();) {
            DocumentListEntry documentListEntry = (DocumentListEntry) iterator
                    .next();
            Log.d("Main","ttDocument title is : " + documentListEntry.title);
        }
    } catch (IOException e) {
            Log.d("Main","Exception getting docs feed : " + e.getMessage());
            //handleException(e);
    }
    Log.d("Main","tDone GoogleDATA API -----------------");