getItemCount doesn't work (FirebaseRecyclerView)

Question

What I am trying to achieve: I have an activity that shows orders if exists but if no orders are found it just shows empty screen (Empty RecyclerView), so if the screen is empty I would like to show a msg to the user or just close the activity by finish();

The Problem: I can't find a way to determine if my adapter has any data! getItemCount always returns zero, and I am not using any listData (ArrayList) I am using Firebase so I don't know how to check total number of items present in recycler view. Help!

Code:

  private void loadOrders(String phone) {
    Query getOrdersByUser = requests.orderByChild("phone").equalTo(phone);
    final FirebaseRecyclerOptions<Request> orderOptions = new FirebaseRecyclerOptions.Builder<Request>()
            .setQuery(getOrdersByUser,Request.class).build();

    adapter = new FirebaseRecyclerAdapter<Request, OrderViewHolder>(orderOptions) {


        @Override
        protected void onBindViewHolder(@NonNull final OrderViewHolder orderViewHolder, final int i, @NonNull final Request model) {

            orderViewHolder.txtOrderId.setText("#"+adapter.getRef(i).getKey());



                orderViewHolder.txtOrderStatus.setText(orderStatus);
                orderViewHolder.txtOrderStatus.setTextColor(Color.GREEN);



        }

        @NonNull
        @Override
        public OrderViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View itemView = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.order_layout,parent,false);
            return new OrderViewHolder(itemView);
        }

        @Override
        public int getItemCount() {
            return super.getItemCount();
        }
    };
    adapter.startListening();
    adapter.notifyDataSetChanged();

    recyclerView.setAdapter(adapter);



}