Can someone please tell the problem with this code?

    public void setupRecyclerView(){
    final String em=mAuth.getCurrentUser().getEmail();
    final String[] id = new String[2];

    cr.addSnapshotListener(new EventListener<QuerySnapshot>() {
        @Override
        public void onEvent(@Nullable QuerySnapshot queryDocumentSnapshots, @Nullable FirebaseFirestoreException e) {
            if(e!=null){
                return;
            }
            Map<String,Object> m = new HashMap<>();
            for (QueryDocumentSnapshot qd : queryDocumentSnapshots){
                User u = qd.toObject(User.class);
                String emd=u.getEmail();
                if(emd.equals(em)){
                 id[0] = qd.getId();
                }

            }
        }
    });

    cr2=cr.document("here it should come").collection("Mailbox");
    Query query = cr2.orderBy("name", Query.Direction.ASCENDING);
    FirestoreRecyclerOptions fcr = new FirestoreRecyclerOptions.Builder<request>().setQuery(query, request.class).build();
    adapter = new ynAdapter(fcr);
    RecyclerView recyclerView=findViewById(R.id.r);
    recyclerView.setHasFixedSize(true);
    recyclerView.setLayoutManager(new LinearLayoutManager(Notification.this));
    recyclerView.setAdapter(adapter);
    }

I am matching email of current user with a specific user's email to get document id but I don't think my for loop is even running.