Как обновить и удалить ПОЛЬЗОВАТЕЛЬ в Firebase - FireStore, а также обновить, удалив аутентификацию пользователя? для Android

Question

Здесь у меня есть вид переработчика, показывающий список документов, извлеченных из ОДНОЙ конкретной коллекции.

По щелчку любого элемента списка, как получить его идентификатор документа и, следовательно, выполнить операции обновления и удаления, тем самым обновляя его в модуле аутентификации FIREBASE AND FIRESTORE ..

public class AllUsers extends AppCompatActivity implements CustomItemClickListener {


FirebaseAuth auth;
FirebaseFirestore db_fr;
ArrayList<RegisterUser> users;
RecyclerView view;
UserRecyclerAdapter adapter;
RegisterUser user;
String docID;
UserId uid;
ArrayList<UserId> idList;

void initViews(){

    auth = FirebaseAuth.getInstance();
    db_fr = FirebaseFirestore.getInstance();
    view = findViewById(R.id.user_recyler);
    LinearLayoutManager linear = new LinearLayoutManager(AllUsers.this);
    view.setLayoutManager(linear);
    users = new ArrayList<>();
    user = new RegisterUser();
    uid = new UserId();
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_all_users);
    initViews();
    fetchAllUsersFromFireStore();
}

void fetchAllUsersFromFireStore(){

    users = new ArrayList<>();
    idList = new ArrayList<>();

    db_fr.collection("Users").get().addOnCompleteListener(this, new OnCompleteListener<QuerySnapshot>() {
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {
            if (task.isSuccessful()){
                for (QueryDocumentSnapshot document : task.getResult()){
                    docID = document.getId();
                    user  = document.toObject(RegisterUser.class);


                    for(DocumentSnapshot doc : task.getResult()) {
                        uid = doc.toObject(UserId.class);
                        uid.doc_ID = doc.getId();
                        idList.add(uid);

                        Log.i("qwe",""+idList);
                    }
                    users.add(user);

                    Toast.makeText(AllUsers.this,"Data Retrieved",Toast.LENGTH_LONG).show();
                    adapter = new UserRecyclerAdapter(AllUsers.this,R.layout.user_list_view,users);
                    view.setAdapter(adapter);
                    adapter.registerCustomItemClickListner(AllUsers.this);

                }

            }else {

                Toast.makeText(AllUsers.this,"Some Error",Toast.LENGTH_LONG).show();
            }
        }
    });
}

@Override
public void onItemClick(View v, int position) {

    user = users.get(position);
    uid = idList.get(position);
    Log.i("idwe",""+uid);
    Log.i("ewdi",""+user.Name);
    showOptions();

    Toast.makeText(AllUsers.this,"--Clickable--"+position,Toast.LENGTH_LONG).show();
}

void showOptions(){
    String[] options = {"View","Delete","Update","Cancel"};
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setItems(options, new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            switch (which){
                case 0:
                    showInfo();
                    break;
                case 1:
                    askForDeletion();

                    break;
                case 2:

                    Intent intent = new Intent(AllUsers.this,RegistrationActivity.class);
                    intent.putExtra("keyUser",user);
                    intent.putExtra("keyID",uid);
                    startActivityForResult(intent,101);
                    break;
                case 3:
                    //finish();
                    break;
            }
        }
    });
    builder.create().show();
}

void showInfo(){
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Details of "+user.Name);
    builder.setMessage(user.toString());
    builder.setPositiveButton("Done",null);
    builder.create().show();
}


void askForDeletion(){
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Delete "+user.Name+" ?");
    builder.setMessage("Are You Sure to delete record?");
    builder.setPositiveButton("Delete", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            deleteUserFromFireStore();
        }
    });
    builder.setNegativeButton("Cancel",null);
    builder.create().show();
}

void deleteUserFromFireStore()
{
  String id = uid.doc_ID;
Log.i("oli",""+id);
    db_fr.collection("Users").document(id).delete()
            .addOnCompleteListener(AllUsers.this, new OnCompleteListener<Void>() {
        @Override
        public void onComplete(@NonNull Task<Void> task) {

            if (task.isSuccessful()){

               Log.i("TASK 1",""+ task.getResult());

                Toast.makeText(AllUsers.this,"User Deleted",Toast.LENGTH_LONG).show();
                users.remove(user);
                adapter.notifyDataSetChanged();

            }else {

                Toast.makeText(AllUsers.this,"Some Error, Deletion Unsuccessfull !",Toast.LENGTH_LONG).show();
            }

        }
    });

}

}

Я использовал разные объектные бины: один с данными пользователя, а другой только для получения идентификатора документа (в чем я не уверен)

Моя регистрационная активность выглядит следующим образом

public class RegistrationActivity extends AppCompatActivity implements View.OnClickListener{

EditText name,contact,email,password;
Button register;
RegisterUser user;
FirebaseAuth auth;
ProgressDialog pd;
FirebaseFirestore db_Firestore;
boolean updateMode;
UserId uid;
String uid1;
Intent rcv;

void initViews(){

    name = findViewById(R.id.textName);
    contact = findViewById(R.id.textContact);
    email = findViewById(R.id.textEmail);
    password = findViewById(R.id.textPassword);
    register = findViewById(R.id.registerBtn);
    register.setOnClickListener(this);
    getSupportActionBar().setTitle("Register");
    pd = new ProgressDialog(this);
    pd.setMessage("Please Wait ..");
    uid = new UserId();
    auth = FirebaseAuth.getInstance();
    db_Firestore = FirebaseFirestore.getInstance();

    rcv = getIntent();
    updateMode = rcv.hasExtra("keyUser");
    if (updateMode) {

        user = (RegisterUser) rcv.getSerializableExtra("keyUser");
        uid = (UserId) rcv.getSerializableExtra("keyID");
        uid1 = uid.doc_ID;
        name.setText(user.Name);
        contact.setText(user.Contact);
        email.setText(user.Email);
        register.setText("Update User");
        register.setOnClickListener(this);
    }

    }
void saveUserInFireStore()
{

    String userid = auth.getCurrentUser().getUid();
    Log.i("userId",""+userid.toString());
    db_Firestore.collection("Users").document(userid)
            .set(user).addOnCompleteListener(this, new OnCompleteListener<Void>() {
        @Override
        public void onComplete(@NonNull Task<Void> task) {
            if (task.isSuccessful()){
                pd.dismiss();

                Toast.makeText(RegistrationActivity.this,"Registration Successfull",Toast.LENGTH_LONG).show();

                Intent intent = new Intent(RegistrationActivity.this,MainActivity.class);
                startActivity(intent);
                finish();

            }else {
                pd.dismiss();
                Toast.makeText(RegistrationActivity.this,"Some Error",Toast.LENGTH_LONG).show();
            }
        }
    }); 
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_registration);
    initViews();
    if (isNetworkConnected()){

        Toast.makeText(this,"Connection Succesfull",Toast.LENGTH_LONG).show();
    }else {

        Toast.makeText(this,"No Internet Connection",Toast.LENGTH_LONG).show();
    }

}

@Override
public void onClick(View v) {


    if (updateMode){

        uid = (UserId)rcv.getSerializableExtra("keyID");
        uid1 = uid.doc_ID;

        user = new RegisterUser();

        user.Name = name.getText().toString().trim();
        user.Contact = contact.getText().toString().trim();
        user.Email = email.getText().toString().trim();
        user.Password = password.getText().toString().trim();

        db_Firestore.collection("Users").document(uid1).set(user);

        Toast.makeText(RegistrationActivity.this,"Updated Successfully ..",Toast.LENGTH_LONG).show();

        Intent intent = new Intent(RegistrationActivity.this,MainActivity.class);
        intent.putExtra("did",uid);
        startActivity(intent);
        finish();


    }else {

    user = new RegisterUser();

    user.Name = name.getText().toString().trim();
    user.Contact = contact.getText().toString().trim();
    user.Email = email.getText().toString().trim();
    user.Password = password.getText().toString().trim();

    pd.show():
    auth.createUserWithEmailAndPassword(user.Email,user.Password).addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
        @Override
        public void onComplete(@NonNull Task<AuthResult> task) {

            if (task.isSuccessful()){


                Toast.makeText(RegistrationActivity.this,"Signed In Successfully ..",Toast.LENGTH_LONG).show();

                saveUserInFireStore();


            }else {

                Toast.makeText(RegistrationActivity.this,"Some Error, Try Again ..",Toast.LENGTH_LONG).show();
                pd.dismiss();

            }

        }
    });
}
}

public boolean isNetworkConnected(){

    ConnectivityManager cm = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);

    if (cm !=null){
        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        return (activeNetwork!=null && activeNetwork.isConnectedOrConnecting());
    }else {
        return false;
    }
}

}

Кроме того, в виде списка при нажатии элемента списка, я перехожу к основной деятельности с выбранными данными пользователя, auth.getCurrentUser (). getUid () возвращает null, и мне нужно получить идентификатор документа, а затем выполнить пересылку, почему это так?

Пожалуйста, помогите!