android - how to implement filterable in RealmRecyclerViewAdapter

Question

I'm using well RealmRecyclerViewAdapter. My problem is to implement a Filterable that not works. This is the code:

 private class AirportAdapter extends RealmRecyclerViewAdapter<AirportR,RecyclerView.ViewHolder> implements Filterable
{
    Context context;
    OrderedRealmCollection<AirportR>listAirports;

    public AirportAdapter(Context activity, OrderedRealmCollection<AirportR>airports)
    {
        super(activity,airports, true);
        this.context = activity;
        this.listAirports = airports;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
    {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.airport_show, parent,false);
        AirportClass holder = new AirportClass(view);
        return holder;

    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position)
    {
       AirportR airportR = listAirports.get(position);

        AirportClass mHolder = (AirportClass)holder;

        mHolder.country.setText(airportR.getIsoCountry());
        mHolder.name.setText(airportR.getName());
    }

    public Filter getFilter()
    {
       AirportFilter filter = new AirportFilter(this, listAirports);
        return filter;
    }


    private class AirportFilter extends Filter
    {
        private final AirportAdapter adapter;

        OrderedRealmCollection<AirportR>originalList;
        OrderedRealmCollection<AirportR>filteredList;


        private AirportFilter(AirportAdapter adapter, OrderedRealmCollection<AirportR> originalList)
        {
            super();
            this.adapter = adapter;
            this.originalList = originalList;

        }


        @Override
        protected FilterResults performFiltering(CharSequence constraint)
        {
            filteredList.clear();
            final FilterResults results = new FilterResults();

            if (constraint.length() == 0)
            {
                filteredList.addAll(originalList);
            }
            else
            {
                final String filterPattern = constraint.toString().toLowerCase().trim();

                for (final AirportR airportR : originalList)
                {
                    if (airportR.getName().toLowerCase().contains(filterPattern))
                    {
                        filteredList.add(airportR);
                    }
                }
            }
            results.values = filteredList;
            results.count = filteredList.size();
            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results)
        {
            adapter.listAirports.addAll((OrderedRealmCollection<AirportR>) results.values);
            adapter.notifyDataSetChanged();
        }
    }



    private class AirportClass extends RecyclerView.ViewHolder
    {
        TextView name, country;
        ImageView image;

        public AirportClass(View itemView)
        {
            super(itemView);

            name = (TextView)itemView.findViewById(R.id.name);
            country = (TextView)itemView.findViewById(R.id.country);
            image = (ImageView)itemView.findViewById(R.id.imageView);

        }
    }
}

and I give back the error:

java.lang.UnsupportedOperationException: This method is not supported by RealmResults.
                  at io.realm.RealmResults.addAll(RealmResults.java:710)
                  at com.example.matteo.downloadairports.fragment.ListAirportFragment$AirportAdapter$AirportFilter.publishResults

how could I save the result after I filter it and update the adapter?

Thanks

Answer 1

Move the filtering to publishResults and use the UI thread Realm's queries to evaluate the new results.

private class AirportAdapter
        extends RealmRecyclerViewAdapter<AirportR, RecyclerView.ViewHolder>
        implements Filterable {
    Realm realm;

    public AirportAdapter(Context context, Realm realm, OrderedRealmCollection<AirportR> airports) {
        super(context, airports, true);
        this.realm = realm;
    }

    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.airport_show, parent, false);
        AirportClass holder = new AirportClass(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
        AirportR airportR = getData().get(position);

        AirportClass mHolder = (AirportClass) holder;
        mHolder.bind(airportR);
    }

    public void filterResults(String text) {
        text = text == null ? null : text.toLowerCase().trim();
        RealmQuery<AirportR> query = realm.where(AirportR.class);
        if(!(text == null || "".equals(text))) {
            query.contains("fieldToQueryBy", text, Case.INSENSITIVE) // TODO: change field
        }
        updateData(query.findAllAsync());
    }

    public Filter getFilter() {
        AirportFilter filter = new AirportFilter(this);
        return filter;
    }

    private class AirportFilter
            extends Filter {
        private final AirportAdapter adapter;

        private AirportFilter(AirportAdapter adapter) {
            super();
            this.adapter = adapter;
        }

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

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            adapter.filterResults(constraint.toString());
        }
    }

    private class AirportClass
            extends RecyclerView.ViewHolder {
        TextView name, country;
        ImageView image;

        public AirportClass(View itemView) {
            super(itemView);

            name = (TextView) itemView.findViewById(R.id.name);
            country = (TextView) itemView.findViewById(R.id.country);
            image = (ImageView) itemView.findViewById(R.id.imageView);
        }

        public void bind(AirportR airportR) {            
            country.setText(airportR.getIsoCountry());
            name.setText(airportR.getName());
        }
    }
}