private void openContact(final int id) {
        final Intent intent = new Intent(Intent.ACTION_VIEW);
        final Uri uri = Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_URI, String.valueOf(id));
        intent.setData(uri);
        activity.startActivity(intent);
    }
Opens a contact in Android with given id
main/src/main/java/cgeo/geocaching/contacts/ContactsHelper.java