Filterable RealmBaseAdapter and AutocompleteTextView

[gpulido]

Hello,
I'm trying to populate an AutocompleteTextView with a list of "RealmResults" and filter the list while the user enter some keys.
I'm extending the RealmBaseAdapter as follows:

public abstract class FilterableRealmBaseAdapter<T extends RealmObject> extends RealmBaseAdapter<T>  implements Filterable{

    RealmResults<T> mRealmObjectList;
    public FilterableRealmBaseAdapter(Context context, RealmResults<T> realmObjectList, AppCompatAutoCompleteTextView refAutocomplete)
    {
        super(context, realmObjectList, true);
        mRealmObjectList  = realmObjectList;
        refAutocomplete.setAdapter(this);

    }

    @Override
    public int getCount() {
        return mRealmObjectList.size();
    }

    @Override
    public T getItem(int position) {
        return mRealmObjectList.get(position);
    }

    @Override
    public Filter getFilter() {
        return new Filter(){

            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                FilterResults result = new FilterResults();
                return result;
            }

            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                RealmResults<T> realmResults = mRealmObjectList.where().contains("name", constraint.toString()).findAll();
                updateRealmResults(realmResults);
            }
        };
    }

AS the Filter class uses the perform filtering on a working thread different that the one is used to create the RealmResults, I just not use that and do the actual filtering process on the publishResults.
The problem is that the list is not being filtered. I have checked the realmResults after the "filter" phase on the publishResults method and it is filtered, but the list on the UI still contains all the items of the original realmResults.

What I am missing here?

Thank you
Gabriel

[zaki50]

@gpulido Thank you for your report.

Filterable support is tracked in #646
I will merge this issue into #646 and will close this.

[saket]

Realm searches are so fast, why do you even need to perform them in a background thread? :)

[gpulido]

@Saketme I'm not, as you can see on the example code, I ignore the performfiltering method (is the one made in background) and do the actual filtering on the publish filter method. The problem is that the list is not being filtered on the UI.

[saket]

Ah. So in the meanwhile, you should try doing it without a Filter class then.

[gpulido]

At this moment I'm just using a ArrayAdapter and handling manually the validation and texteditchanged but it is very patchy.

[freezy]

@gpulido, do you have a snippet of your workaround to share?

[gpulido]

@freezy I had to create a "mini POCO class" with just the basic info I need ffrom the original RealmObject, and transforming the RealmResults list to a list of this POCO class before creating a basic arrayAdapter. So at the end I'm holding a "non realm supported" list. As I'm using this just for a spinner that is being populated almost every time, it is not a problem. It is not the best or prettier solution but it works for me until Realm comes with a cleaner solution.
If you need the code for the filterable array adapter I could write it here, but once you are not using a RealmResult but a transformation of it (using Streams it is very straightforward and clean) it is not a "Realm based" solution anymore.

[freezy]

I've tried something like this and filtering seems to work so far:

public class FilterableRealmAdapter<T extends RealmObject> extends ArrayAdapter<T> implements Filterable {

    final RealmResults<T> mRealmObjectList;
    List<T> mResults;

    public FilterableRealmBaseAdapter(Context context, RealmResults<T> realmObjectList, MaterialAutoCompleteTextView refAutocomplete) {
        super(context, android.R.layout.simple_list_item_1);
        mRealmObjectList = realmObjectList;
        refAutocomplete.setAdapter(this);
    }

    @Override
    public int getCount() {
        return mResults == null ? 0 : mResults.size();
    }

    @Override
    public T getItem(int position) {
        return mResults == null ? null : mResults.get(position);
    }

    @Override
    public Filter getFilter() {
        return new Filter() {

            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                return new FilterResults();
            }

            @Override
            protected void publishResults(CharSequence constraint, FilterResults results) {
                if (constraint != null) {
                    mResults = mRealmObjectList.where().contains("name", String.valueOf(constraint)).findAll();
                    notifyDataSetChanged();
                }
            }
        };
    }
}

However, still need to figure out how to nicely populate the view, but this isn't Realm related.

It would be interesting to see your solution as well.

[saket]

There's one gotcha here if you're using an adapter based EditText (AutocompleteTextView, etc.). In the FilterResults object you're returning from performFiltering, make sure you set its count value > 0 or else the auto-complete dropdown will flicker every time the data-set is updated.

(To be more precise, AutocompleteTextView uses the count value to decide whether or not to show the dropdown. Returning 0 will cause it to hide and re-appear again when notifyDataSetChanged is called)

[gpulido]

@freezy Your solution is very similar to my first approach (at the top of this issue), but you manage to solve the substitution of the filtered list (I don't know why I didn't figure out that way).
I'm going to change my code to use your approach and get ride of the streams and "POCO" class.
What is the problem you are having with the view? You already have solved the hard part.

[freezy]

Alright, thanks for commenting. No particular problem with the view, I just hadn't done it at the time I posted the comment.

I'll paste the refactored class with @Saketme's input in #646.

[rahulbharsadiya]

Realm searches are so fast, why do you even need to perform them in a background thread? :)

Hey,can you provide an example code on autocomplete textview ,where we put the filter data from realm objects,am a newbee,please do help

[Zhuinden]

https://stackoverflow.com/a/44602748/2413303