android pokedex

public class PokedexAdapter extends RecyclerView.Adapter<PokedexAdapter.PokedexViewHolder> implements Filterable {
    private List<Pokemon> pokemon = new ArrayList<>();
    private List<Pokemon> filtered = new ArrayList<>();
    private RequestQueue requestQueue;

public static class PokedexViewHolder extends RecyclerView.ViewHolder {
        public LinearLayout containerView;
        public TextView textView;


        public PokedexViewHolder(View view) {
            super(view);

            containerView = view.findViewById(R.id.pokedex_row);
            textView = view.findViewById(R.id.pokedex_row_text_view);

            containerView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Pokemon current = (Pokemon) containerView.getTag();
                    Intent intent = new Intent(v.getContext(), PokemonActivity.class);
                    intent.putExtra("url", current.getUrl());

                    v.getContext().startActivity(intent);
                }
            });
        }
    }

    public PokedexAdapter(Context context) {
        requestQueue = Volley.newRequestQueue(context);
        loadPokemon();
    }

    public void loadPokemon() {
        String url = "https://pokeapi.co/api/v2/pokemon?limit=151";
        JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                try {
                    JSONArray results = response.getJSONArray("results");
                    for (int i = 0; i < results.length(); i++) {
                        JSONObject result = results.getJSONObject(i);
                        String name = result.getString("name");
                        pokemon.add(new Pokemon(
                            name.substring(0, 1).toUpperCase() + name.substring(1),
                            result.getString("url")
                        ));
                    }

                    filtered = pokemon;
					notifyDataSetChanged();
                } catch (JSONException e) {
                    Log.e("cs50", "Json error", e);
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.e("cs50", "Pokemon list error", error);
            }
        });

        requestQueue.add(request);
    }

	@Override
    public PokedexViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.pokedex_row, parent, false);

        return new PokedexViewHolder(view);
    }
    @Override
    public void onBindViewHolder(@NonNull PokedexViewHolder holder, int position) {
        Pokemon current = filtered.get(position);
        holder.textView.setText(current.getName());
        holder.containerView.setTag(current);
    }

    @Override
    public Filter getFilter() {
        return new PokemonFilter();
    }

    private class PokemonFilter extends Filter{

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            FilterResults results = new FilterResults();
            String filterString = constraint.toString().toLowerCase();

            if (filterString.isEmpty()){
                results.values = pokemon;
                results.count = pokemon.size();
            } else {
                List<Pokemon> filteredPokemon = new ArrayList<>();
                for (Pokemon item : pokemon) {
                    if (item.getName().toLowerCase().contains(filterString)) {
                        filteredPokemon.add(item);
                    }
                }
                results.values = filteredPokemon;
                results.count = filteredPokemon.size();
            }

            return results;
        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            filtered = (List<Pokemon>) results.values;
            notifyDataSetChanged();
        }
    }

    @Override
    public int getItemCount() {
        return filtered.size();
    }