这是在安卓Jetpack ViewModel的Firestore中使用查询的正确方式吗？

FirebaseFirestore db = FirebaseFirestore.getInstance();
Query query = db.collection("users").where("age", ">=", 18);

public class UserViewModel extends ViewModel {
    private MutableLiveData<List<User>> users;

    public LiveData<List<User>> getUsers() {
        if (users == null) {
            users = new MutableLiveData<>();
            loadUsers();
        }
        return users;
    }

    private void loadUsers() {
        query.addSnapshotListener((queryDocumentSnapshots, e) -> {
            if (e != null) {
                // 处理错误
                return;
            }

            List<User> userList = new ArrayList<>();
            for (QueryDocumentSnapshot document : queryDocumentSnapshots) {
                User user = document.toObject(User.class);
                userList.add(user);
            }
            users.setValue(userList);
        });
    }
}

public class MainActivity extends AppCompatActivity {
    private UserViewModel userViewModel;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        userViewModel = new ViewModelProvider(this).get(UserViewModel.class);
        userViewModel.getUsers().observe(this, userList -> {
            // 更新UI
        });
    }
}