Adapter

public class CustomAdapter extends RecyclerView.Adapter<ViewHolder> {

    ListActivity listActivity;
    List<Collection> collectionList;


    public CustomAdapter(ListActivity listActivity, List<Collection> collectionList) {
        this.listActivity = listActivity;
        this.collectionList = collectionList;
    }

    @NonNull
    @NotNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull @NotNull ViewGroup viewGroup, int i) {
        View itemView = LayoutInflater.from(viewGroup.getContext())
                .inflate(R.layout.collection_layout, viewGroup, false);


        ViewHolder viewHolder = new ViewHolder(itemView);

        viewHolder.setOnClickListener(new ViewHolder.ClickListener() {
            @Override
            public void onItemClick(View view, int position) {

//                показ данных в тосте при клике
                String title = collectionList.get(position).getTile();
                // image todo


                Toast.makeText(listActivity, title+"\n"
                                /// todo description
                        , Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onItemLongClick(View view, int position) {

            }
        });
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(@NonNull @NotNull ViewHolder viewHolder, int position) {
        viewHolder.rTitle.setText(collectionList.get(position).getTile());
        //image TODO
    }

    @Override
    public int getItemCount() {
        int a ;

        if(collectionList != null && !collectionList.isEmpty()) {

            a = collectionList.size();
        }
        else {

            a = 0;

        }

        return a;
    }
}