CODEWITHSUNDEEP
androiddatabaserealmrx-java
xhinliang
xhinliang

Reputation: 164

Realm DB Realm.asObservable() emits results twice

I use RxJava and Realm DB for my application. When I query the data in the Realm and call Realm.asObservable(),The RealmResult emits 2 times.

public class JustTest extends Activity {
    private static final String TAG = "TEST";
    private Realm realm;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        realm = Realm.getDefaultInstance();
        realm.where(Group.class).findAllAsync().asObservable()
                .subscribe(new Action1<RealmResults<Group>>() {
                    @Override
                    public void call(RealmResults<Group> groups) {
                        XLog.d(TAG, "Realm launch group result, size " + groups.size());
                    }
                });
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        realm.close();
    }
}

Log:

TEST: Realm emits group result, size 0
TEST: Realm emits group result, size 1

Upvotes: 2

Views: 931

Answers (1)

Christian Melchior
Christian Melchior

Reputation: 20126

That is by design, as Realm emits a placeholder object immediately if you subscribe to it. If you are only interested in the first "real" result you can do something like this:

realm.where(Foo.class).findAllAsync().asObservable()
  .filter(obj::isLoaded) // isLoaded is true when query is completed
  .first() // Only get the first result and then complete
  .subscribe(...)

This is not immediately clear from the current documentation, but we are in the process of updating the JavaDoc to explain this better: https://github.com/realm/realm-java/pull/2201

Upvotes: 5

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