Troubleshooting Password Validation Issues in Transaction App: Incomplete Execution of passCheck Function

Question

I am developing an application for conducting transactions, and I've implemented a password validation feature before proceeding with any transactions. Within the app, there's a function called passCheck, which retrieves a value from Firebase Realtime Database and compares it with the password entered by the user.

However, I've encountered an issue where the app functions correctly the first time around. But subsequent attempts to perform transactions before closing the app result in an "Incorrect password" message, even when the correct password is entered.

private void passCheck(final String enteredPassword, final PassCheckCallback callback) {
        DatabaseReference usersRef = FirebaseDatabase.getInstance().getReference().child("users");
        Query query = usersRef.child("Reg_Users").orderByChild("userId").equalTo(userId);
        Log.d("passCheck ", "Checking...."+enteredPassword.toString());
        query.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    String upiPass = snapshot.child("upi_pass").getValue(String.class);
                    // Compare entered password with retrieved upi_pass
                    Log.d("passCheck",upiPass.toString());
                    if (upiPass != null && upiPass.equals(enteredPassword)) {
                        callback.onPassChecked(true); // Password matches
                        upiPass="";
                        return;
                    }
                }
                // Password doesn't match or upi_pass not found
                callback.onPassChecked(false);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
                // Handle potential errors here
                callback.onPassChecked(false); // Notify callback about failure
            }
        });
    }

The Function is then used here

btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                progressBar.setVisibility(View.VISIBLE);
                String enteredPassword = password.getText().toString();
                Log.d("Password",enteredPassword.toString());

                // Check the entered password
                passCheck(enteredPassword, new PassCheckCallback() {
                    @Override
                    public void onPassChecked(boolean isCorrect) {
                        if (isCorrect) {
                            // Password is correct, proceed with updating balance and transferring money
                            updateBalance();
                            usersTransaction();
                            progressBar.setVisibility(View.INVISIBLE);
                            Intent intent = new Intent(password_validate.this,MainActivity.class);
                            startActivity(intent);
                            finish();
                        } else {
                            progressBar.setVisibility(View.INVISIBLE);
                            // Password is incorrect, show error message
                            Toast.makeText(password_validate.this, "Incorrect password", Toast.LENGTH_SHORT).show();
                        }
                    }
                });
            }
        });

To troubleshoot this issue, I've added logging to track the execution flow. It appears that on the second attempt, the passCheck function only executes up until the query.addListenerForSingleValueEvent stage.