realm-java: RealmChangeListener on empty RealmResults never fires

See https://realm.io/docs/java/latest/api/io/realm/RealmResults.html

Adds a change listener to this RealmResults. Registering a change listener will not prevent the underlying RealmResults from being garbage collected. If the RealmResults is garbage collected, the change listener will stop being triggered. To avoid this, keep a strong reference for as long as appropriate e.g. in a class variable.

 public class MyActivity extends Activity {

     private RealmResults<Person> results; // Strong reference to keep listeners alive

     @Override
     protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       results = realm.where(Person.class).findAllAsync();
       results.addChangeListener(new RealmChangeListener<RealmResults<Person>>() {
           @Override
           public void onChange(RealmResults<Person> persons) {
               // React to change
           }
       });
     }
 }

On top of that, you’re calling copyFromRealm instead of, like, copyToRealmOrUpdate or insertOrUpdate or anything that actually writes into the db. Also, running synchronous transaction inside a change listener?

Are you trying to get an infinite loop? 😕

What are you doing???

@kneth sorry I haven’t got a chance to try. Crazy sprints at work.

@beeender I haven’t been able to set aside time for it yet.

Deletion is fine. I just want to make sure other objects aren’t added.

I changed my process to copy from the RealmResults, and do an in query later to delete them. Less performant, but it works.

I’ll have to revisit later, but I believe that the filter on non empty (this time on the unmanaged list) still caused the issue where the RealmChangeListener wouldn’t fire. At this point not sure if it’s a realm issue, an rx issue, or both. I’ll update when I make a sample project.