Firebase read and onClick handler Error in reading the Firebase value: pricecode

Question

Please tell me specifically how to fix the function so that when the button is clicked (onclick handler) passes the value from the database to the firebase USER - "price" branch. I can't figure it out for about two days. I will be grateful for a concrete example and correction of my function. Thanks. enter image description here

public void onClickB1 (View view)

{
    DatabaseReference db = FirebaseDatabase.getInstance().getReference();
    DatabaseReference userRef = db.child("User");
    userRef.get().addOnCompleteListener(new OnCompleteListener<DataSnapshot>() {
        @Override
        public void onComplete(@NonNull Task<DataSnapshot> task) {
            if (task.isSuccessful()) {
                DataSnapshot snapshot = task.getResult();
                String priceCode = snapshot.child("pricecode").getValue(String.class);
                Log.d("TAG", "priceCode: " + priceCode);
                String id = db.getKey();
                String name = "s";
                String price = String.valueOf(snapshot.getValue());
                User newUser = new User(id,name,price);
                db.push().setValue(newUser);
            } else {
                Log.d("TAG", task.getException().getMessage()); //Never ignore potential errors!
            }
        }
    });
}