android - Realm Change Listener with RealmResults not being called

Question

I'm using Realm 3.0.0

I'm fetching some objects from Realm and trying to add onChangeListener, but it does not get fired when an object is changed

Here's the code, am I missing something here?

 RealmResults<Record> realmResults = RealmManager.recordsDao().loadRecords();
    realmResults.addChangeListener(new RealmChangeListener<RealmResults<Record>>() {
        @Override
        public void onChange(RealmResults<Record> element) {
            for (int i = 0; i < recordList.size(); i++) {
                if (collection.get(i).getId().equals(recordList.get(i).getId())) {
                    recordList.set(i, collection.get(i));
                    adapter.notifyItemChanged(i);
                }

            }
        }
    });

Also as per the docs, it mentions to call invalidateView(); but even that does not reflect the new data

The change to the object is made in the adapter

public class RecordsAdapter extends RecyclerView.Adapter<RecordsAdapter.ViewHolder> {

private ArrayList<Record> recordList;
private Context context;
private Realm realm = Realm.getDefaultInstance();

public RecordsAdapter(ArrayList<Record> recordList, Context context) {
    this.recordList = recordList;
    this.context = context;
}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_records, parent, false);
    return new ViewHolder(v);
}


@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    holder.batsmanName.setText(recordList.get(position).getName());
    Glide.with(context).load(recordList.get(position).getImage()).diskCacheStrategy(DiskCacheStrategy.SOURCE).into(holder.profilePicture);
    holder.totalRuns.setText("Runs " + recordList.get(position).getTotalScore());
    holder.totalMatches.setText("Matches " +recordList.get(position).getMatchesPlayed());


    if (recordList.get(position).isFavourite())
        holder.favCheck.setChecked(true);
    else
        holder.favCheck.setChecked(false);


    holder.favCheck.setOnClickListener(v -> {
        CheckBox checkBox = (CheckBox) v;
        if (checkBox.isChecked()) {
            realm.executeTransaction(realm1 -> {
                recordList.get(position).setFavourite(true);
                realm.copyToRealmOrUpdate(recordList);
            });
        } else {
            realm.executeTransaction(realm12 -> {
                recordList.get(position).setFavourite(false);
                realm.copyToRealmOrUpdate(recordList);
            });
        }

    });


}

Answer 1

You need to store the RealmResults as a field reference in order to ensure that Realm can update it

RealmResults<Record> realmResults;

public void etc() {
    realmResults = RealmManager.recordsDao().loadRecords();
    realmResults.addChangeListener(new RealmChangeListener<RealmResults<Record>>() {

Also, you should probably use RealmRecyclerViewAdapter from https://github.com/realm/realm-android-adapters with RealmResults<Record>, instead of ArrayList so that you actually keep a managed results in sync with your recycler view automatically

---

So with that in mind, all you need to do is replace your code with

public class RecordsAdapter extends RealmRecyclerViweAdapter<Record, RecordsAdapter.ViewHolder> {
     public RecordsAdapter(OrderedRealmCollection<Record> realmResults) {
         super(realmResults, true);
     }

     // ... same as before
}

and

recyclerView.setAdapter(new RecordsAdapter(RealmManager.recordsDao().loadRecords());

And just ditch your RealmChangeListener because it is incomplete and unnecessary