try {
PeopleService peopleService = PeopleService.getInstance();
GetPersonRequestBuilder builder = peopleService
.newGetViewerRequestBuilder();
builder.setFields("thumbnailUrl", "name");
OsapiRequest<Person> viewer = builder.build();
Callback<Person> callback = new Callback<Person>() {
@Override
public void onFail(OsapiError error) {