Código del ejercicio con el RecyclerView usando View Binding

Código del ejercicio que muestra los contactos en un RecyclerView usando View Binding

Contacto

public class Contact {
    private String mName;
    private boolean mOnline;

    public Contact(String name, boolean online) {
        mName = name;
        mOnline = online;
    }

    public String getName() {
        return mName;
    }

    public boolean isOnline() {
        return mOnline;
    }

    private static int lastContactId = 0;

    public static ArrayList<Contact> createContactsList(int numContacts) {
        ArrayList<Contact> contacts = new ArrayList<Contact>();

        for (int i = 1; i <= numContacts; i++) {
            contacts.add(new Contact("Person " + ++lastContactId, i <= numContacts / 2));
        }

        return contacts;
    }
}

ContactsAdapter

/**
 * Adaptador que gestiona una lista de Contactos
 */
public class ContactsAdapter extends RecyclerView.Adapter<ContactsAdapter.ContactViewHolder> {

    private List<Contact> list;
    private OnItemClickListener listener;

    //Interfaz para el evento onClick de un elemento del RecyclerView
    public interface OnItemClickListener {
        void onItemClick(Contact Contact);
    }

    //Constructor que se le pasa la lista de notas y el listener
    public ContactsAdapter(List<Contact> list, OnItemClickListener listener) {
        this.list = list;
        this.listener=listener;
    }

    @Override
    public ContactViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        // return new ContactViewHolder(ItemContactBinding.inflate(LayoutInflater.from(parent.getContext()), parent, false));

        LayoutInflater inflater = LayoutInflater.from(parent.getContext());

        ItemContactBinding binding = ItemContactBinding.inflate(inflater, parent, false);

        return new ContactViewHolder(binding);
    }

    //Método que vincula cada dato con la vista
    @Override
    public void onBindViewHolder(ContactViewHolder holder, int position) {
        Contact Contact = list.get(position);
        holder.binding.contactName.setText(Contact.getName());
        holder.binding.messageButton.setText(Contact.isOnline() ? "Message" : "Offline");
        holder.binding.messageButton.setEnabled(Contact.isOnline());
        holder.bind(list.get(position), listener);
    }

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

    /**
     * Clase ViewHolder
     */

    public class ContactViewHolder extends RecyclerView.ViewHolder {
        ItemContactBinding binding;
        //public TextView title, content;

        public ContactViewHolder(ItemContactBinding b) {
            //super(view);
            //title = view.findViewById(R.id.title);
            //content = view.findViewById(R.id.content);
            super(b.getRoot());
            binding = b;
        }

        public void bind(final Contact Contact, final OnItemClickListener listener) {
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    listener.onItemClick(Contact);
                }
            });
        }
    }
}

MainActivity

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    ArrayList<Contact> contacts;
    RecyclerView rvContacts;
    Button addMoreButton;
    ActivityMainBinding binding;
    ContactsAdapter adapter;
    ContactsAdapter.OnItemClickListener listener;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = ActivityMainBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        // Initialize contacts
        contacts = Contact.createContactsList(20);
        // Create adapter passing in the sample user data
        listener = new ContactsAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(Contact contact) {
                Toast.makeText(MainActivity.this, "Contacto seleccionado: " + contact.getName(), Toast.LENGTH_LONG).show();
            }
        };
        adapter = new ContactsAdapter(contacts, listener);
        // Attach the adapter to the recyclerview to populate items
        binding.rvContacts.setAdapter(adapter);
        // Set layout manager to position the items
        binding.rvContacts.setLayoutManager(new LinearLayoutManager(this));

        binding.addContact.setOnClickListener(this);

        //adapter.setOnItemClickListener(this);

        // That's all!
    }

    @Override
    public void onClick(View view) {
        // record this value before making any changes to the existing list
        int curSize = adapter.getItemCount();
        // Add a new contact
        // contacts.add(0, new Contact("Barney", true));
        // Notify the adapter that an item was inserted at position 0
        // adapter.notifyItemInserted(0);
        contacts.add(curSize, new Contact("Barney", true));
        adapter.notifyItemInserted(curSize);
    }

}

Repositorio en GitLab: Contactos