RealmResults对象获得恒定的NPE

Question

我收到一个错误：Unable to destroy activity: java.lang.NullPointerException: Attempt to invoke virtual method 'void io.realm.RealmResults.removeAllChangeListeners()' on a null object reference

代码：

@Override
protected void onDestroy() {
    if (realmResult != null) {
        realmResult.removeAllChangeListeners();
    }
    mRealm.close();
    super.onDestroy();
}

我仍然有NPE。在致电removeAllChangeListeners()之前，我还应该检查一些其他东西吗？