Develop Reference

How can we store dropdown selected option string to firestore in android studio

I have String list as shown I want the selected item to be store in Firestore
Can you please tell me how it should be possible?
I have String list as shown I want the selected item to be store in Firestore
Can you please tell me how it should be possible?
public class Student_Register_Activity extends AppCompatActivity {
EditText etRegEmail,etname,etfathername,etRollno,etdepartment,etadress,etphonenmbr,semester,;
EditText etRegPassword;
String[] items={"Shinkiari","Mansehra","Abbottabad","Qalandarabad","Attersheesha","Khaki"};
AutoCompleteTextView autoCompleteText;
Button btnRegister;
ArrayAdapter<String> adapteritems;
FirebaseAuth mAuth;
FirebaseFirestore firestore=FirebaseFirestore.getInstance();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_student_register);
autoCompleteText=findViewById(R.id.auto_complete_txt);
adapteritems=new ArrayAdapter<String>(this,R.layout.list_item,items);
autoCompleteText.setAdapter(adapteritems);
autoCompleteText.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
String item =adapterView.getItemAtPosition(position).toString();
}
});
etRegEmail = findViewById(R.id.etRegEmail);
etRegPassword = findViewById(R.id.etRegPass);
btnRegister = findViewById(R.id.btnRegister);
etname = findViewById(R.id.etname);
etfathername = findViewById(R.id.etfname);
etRollno = findViewById(R.id.etRollno);
etdepartment = findViewById(R.id.etdepartment);
etadress = findViewById(R.id.etadress);
etphonenmbr = findViewById(R.id.etphonenmbr);
mAuth = FirebaseAuth.getInstance();
btnRegister.setOnClickListener(view -> createUser());
}
private void createUser(){
String email = etRegEmail.getText().toString();
String password = etRegPassword.getText().toString();
if (TextUtils.isEmpty(email)){
etRegEmail.setError("Email cannot be empty");
etRegEmail.requestFocus();
}else if (TextUtils.isEmpty(password)){
etRegPassword.setError("Password cannot be empty");
etRegPassword.requestFocus();
}else{
mAuth.createUserWithEmailAndPassword(email,password).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
#Override
public void onComplete(#NonNull Task<AuthResult> task) {
if (task.isSuccessful()){
Toast.makeText(Student_Register_Activity.this, "Student registered successfully", Toast.LENGTH_SHORT).show();
FirebaseUser user = mAuth.getCurrentUser();
DocumentReference df = firestore.collection("Student").document(user.getUid());
//Map is used to store the data
Map<String,Object> userinfo = new HashMap<>();
userinfo.put("Name",etname.getText().toString());
userinfo.put("FName",etfathername.getText().toString());
userinfo.put("Email",etRegEmail.getText().toString());
userinfo.put("Password",etRegPassword.getText().toString());
userinfo.put("semester",etRegPassword.getText().toString());
userinfo.put("Transport", adapteritems.toString();
userinfo.put("Rollno",etRollno.getText().toString());
userinfo.put("Department",etdepartment.getText().toString());
userinfo.put("address",etadress.getText().toString());
userinfo.put("phone",etphonenmbr.getText().toString());
startActivity(new Intent(Student_Register_Activity.this, AdminDashboard.class));
//specify if user is student
userinfo.put("isStudent","1");
df.set(userinfo);
}else{
Toast.makeText(Student_Register_Activity.this, "Registration Error: " + task.getException().getMessage(), Toast.LENGTH_SHORT).show();
}
}
});
}
}
}

I think you want to add selected items from list in user object, If that so you can follow below steps:
first declare global variable for selected
String selectedOption;
Then save value in on click of list
autoCompleteText.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
selectedOption =adapterView.getItemAtPosition(position).toString();
}
});
then use that value to save in user object
userinfo.put("city",selectedOption);

How to save the state of button onced pressed

I just fetch data & load it into recyclerView that can be set on adapter. It contains a button which is able to send data to Firebase.
When I press the button its color and text changes as per requirement
but whenever I reload it again the default button state gets loaded.
So I want that button should save its state once clicked and whenever I reload the same activity it should be in the saved state.
viewHolder.send_req.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(final View v) {
final Integer taggedPosition = viewHolder.getAdapterPosition();
Log.d(TAG,"button click data:"+taggedPosition);
firebaseFirestore.collection("Users").document(u_id).get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
#Override
public void onComplete(#NonNull Task<DocumentSnapshot> task) {
if (task.getResult().exists()){
name = task.getResult().getString("name");
userID = task.getResult().getString("user_id");
firebaseFirestore.collection("Pets").whereEqualTo("name",name_data).get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
#Override
public void onComplete(#NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()){
for (final DocumentSnapshot documentSnapshot : task.getResult()){
docID = documentSnapshot.getId();
Log.d(TAG,"selected pet doc id:"+docID);
if (docID!= null){
final Map<String, Object> userMap = new HashMap<>();
final Map<String, Object> userMap1 = new HashMap<>();
userMap.put("doc_id",docID);
userMap.put("pet_id",pet_no);
userMap.put("sender_id",userID);
userMap.put("sender_name",name);
userMap.put("pet_name",name_data);
userMap.put("pet_profile",image_url);
userMap.put("timestamp",FieldValue.serverTimestamp());
//do not place request if data is already exist in document
firebaseFirestore.collection("Send_req").get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
#Override
public void onComplete(#NonNull Task<QuerySnapshot> task) {
List<String> list = new ArrayList<>();
final Button send_req = (Button)v;
if (task.isSuccessful()){
for (DocumentSnapshot document : task.getResult()) {
list.add(document.getString("doc_id"));
list.add(document.getString("sender_id"));
}
if (!(list.contains(docID)&& list.contains(userID))){
send_req.setClickable(true);
Toast.makeText(context,"send request successfully",Toast.LENGTH_SHORT).show();
send_req.setText("Cancel Request");
send_req.setBackgroundColor(Color.RED);
String btnname =send_req.getText().toString();
String button_name = (String)userMap.put("btnName",btnname);
firebaseFirestore.collection("Send_req").add(userMap);
send_req.setClickable(false);
}
else {
if ((list.contains(docID)&& list.contains(userID))){
if(send_req.getText().toString().equals("Send Request") )
Toast.makeText(context,"you already send request",Toast.LENGTH_SHORT).show();
send_req.setText("Cancel Request");
send_req.setBackgroundColor(Color.RED);
send_req.setClickable(false);
notifyDataSetChanged();}
}
}
}
});
}
}
}
}
});
}
}
});
}
});

public class SomeClass {
public static boolean isFeatureSelected = false;
...
}
And you can always invoke it with SomeClass.isFeatureSelected.

If you already have the pojo of the response then you can define a variable in the pojo and change the value on button click on that position. As define by ChrisZ.
But if as you don't have pojo I will suggest you to create a List of Boolean size same as the recyclerView item size with false value. Once you click on the button make the list boolean to true at that position so you can know on which position you already clicked and change the UI with the bool value at that position.

Create a boolean variable such as:
boolean isClicked = false; and int pos = -1;
Then the first time you changed the button background change the boolean to true and pos = position;.
Then in the onBindViewHolder of your RecyclerView do this:
if(isClicked && position == pos){ // check the state of the button and the adapter position.
// change your background here
}

How to write Shared preference Code that uses firebase for User authentication?

How do I write Shared-preference Code that is using Firebase for User authentication and the data that is saved by a user is only accessible for them?
My current application Saves a note and displays it which is the main thing needed in my project but when a user logs out and new user logs in he/she can also view the data so the data is not private. My sir suggested to make nodes for users using shared preference but i couldn't find any solutions
HomeActivity:
public class HomeActivity extends AppCompatActivity {
EditText Descriptionholder;
Button Savebtn;
DatabaseReference DatabaseNote;
ListView listViewNotes;
List<PrivateNote> privateNoteList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
DatabaseNote = FirebaseDatabase.getInstance().getReference("privatenote");
Descriptionholder = findViewById(R.id.description2);
Savebtn = findViewById(R.id.buttonsave);
listViewNotes= findViewById(R.id.listViewPrivate);
privateNoteList = new ArrayList<>();
Savebtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
addnote();
}
});
listViewNotes.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> adapterView, View view, int i, long l) {
PrivateNote privateNote = privateNoteList.get(i); //confusion
showUpdateDialog(privateNote.getNoteId(),privateNote.getNoteDescription());
return false;
}
});
}
public boolean onCreateOptionsMenu (Menu menu){
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.side, menu);
return true;
}
#Override
public boolean onOptionsItemSelected (MenuItem item){
switch (item.getItemId()) {
case R.id.item1:
FirebaseAuth.getInstance().signOut();
finish();
startActivity(new Intent(new Intent(this, MainActivity.class)));
Toast.makeText(this, "Logged out ", Toast.LENGTH_SHORT).show();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
#Override
protected void onStart() {
super.onStart();
DatabaseNote.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
privateNoteList.clear();
for (DataSnapshot privateSnapshot: dataSnapshot.getChildren() ){
PrivateNote privateNote = privateSnapshot.getValue(PrivateNote.class);
privateNoteList.add(privateNote);
}
PrivateList adapter = new PrivateList(HomeActivity.this,privateNoteList);
listViewNotes.setAdapter(adapter);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
private void showUpdateDialog(final String noteId, String noteDescription){
AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
LayoutInflater inflater = getLayoutInflater();
final View dialogview = inflater.inflate(R.layout.update_dialouge,null);
dialogBuilder.setView(dialogview);
final EditText editDescription = dialogview.findViewById(R.id.editDescription);
final Button buttonUpdate = dialogview.findViewById(R.id.buttonUpdate);
final Button buttonDelete = dialogview.findViewById(R.id.buttonDelete);
dialogBuilder.setTitle("Updating Note: " +noteDescription);
final AlertDialog alertDialog = dialogBuilder.create();
alertDialog.show();
buttonUpdate.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String description = editDescription.getText().toString().trim();
if (TextUtils.isEmpty(description)){
editDescription.setError(" New information required");
return;
}
updatePrivateNote(noteId,description);
alertDialog.dismiss();
}
});
buttonDelete.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
deletePrivateNote(noteId);
}
});
}
private void deletePrivateNote(String noteId) {
DatabaseReference drPrivateNote = FirebaseDatabase.getInstance().getReference("privatenote").child(noteId);
drPrivateNote.removeValue();
Toast.makeText(this, " Note Deleted", Toast.LENGTH_SHORT).show();
}
private boolean updatePrivateNote(String id,String description){
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("privatenote").child(id);
PrivateNote privateNote = new PrivateNote(id,description);
databaseReference.setValue(privateNote);
Toast.makeText(this, " Note Updated", Toast.LENGTH_SHORT).show();
return true;
}
private void addnote () {
String description = Descriptionholder.getText().toString().trim();
if (!TextUtils.isEmpty(description)){
//generated unique number for id
String id = DatabaseNote.push().getKey();
PrivateNote pNote = new PrivateNote(id, description);
DatabaseNote.child(id).setValue(pNote); //pNote value added in id
Toast.makeText(this, "Note added", Toast.LENGTH_SHORT).show();
}
else {
Toast.makeText(this, " Please Enter a note ", Toast.LENGTH_SHORT).show();
}
}
#Override
public void onBackPressed() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
FirebaseAuth.getInstance().signOut();
finish();
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
alert.show();
}
Adapter:
public class PrivateList extends ArrayAdapter<PrivateNote> {
private Activity context;
private List<PrivateNote> privateNoteList;
public PrivateList(Activity context, List<PrivateNote> privateNoteList){
super(context, R.layout.list_layout,privateNoteList);
this.context =context;
this.privateNoteList=privateNoteList;
}
#NonNull
#Override
public View getView(int position, #Nullable View convertView, #NonNull ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View listViewItem = inflater.inflate(R.layout.list_layout,null,true);
TextView textViewDescription = listViewItem.findViewById(R.id.TextViewDescription);
PrivateNote privateNote = privateNoteList.get(position);
textViewDescription.setText(privateNote.getNoteDescription());
return listViewItem;
}
}
PrivateNote:
public class PrivateNote {
public String noteId;
public String noteDescription;
public PrivateNote(){
}
PrivateNote(String noteId, String noteDescription){
this.noteId = noteId;
this.noteDescription=noteDescription;
}
String getNoteId()
{
return noteId;
}
String getNoteDescription()
{
return noteDescription;
}
}

In Firebase, there are two things,
FirebaseDatabase
FirebaseAuth
Usually, in almost all the apps, user data is stored in the FirebaseDatabase under the key, that is generated while creating a new user in your Firebase app.
So, for example, your database structure will look like this.
-Your_main_database
|____UserId_Of_FirebaseUser
|____stuff_related_to_user
|____More stuff related to user
So, you create a new user in FirebaseAuth, you can find more about it below:
Firebase Custom Auth.
Then, after creating a new user, you create child nodes under your database with the key=userId of your current logged in user.
eg. In your addNote function, the id variable will be equal to
String id = FirebaseAuth.getInstance().getCurrentUser().getUid();
Currently, you're using Push keys which are generated based on Timestamp, which you won't be able to associate with user unless you add a key inside your note object which stored current username, and then find all the child nodes that contain that username, but in that case, your data won't be organized at all.
Then, after you create a node with userId under your main database, you can then push new notes created by your user inside the userId with the push() function. So your database structure will look like below.
___
|
|__users
|__uniqueUserId
| |__note1
| |__note2
|__uniqueUserId2
|__note1
|__note2
|__note3
Next time whenever you want to fetch user created notes, you log in the user, get his ID, and then find the notes corresponding to that ID.
I don't see how you can fit SharedPreferences in there, before there is also function to cache data offline in Firebase once it is loaded.
Securing the notes:
If you implement the database like I said above, you'll be very easily able to secure your database.
Common Database Rules.
If you implement everything correctly like I told, you'll be able to secure your database with the fourth set of rules from above rules.

Since you are using firebase authentication, then you can retrieve the userId, and create the following database:
notes
userId
note : "todo"
description : "study"
Then you can do:
DatabaseReference ref = FirebaseDatabase.getInstance().getReference("notes");
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
String userId = user.getUid();
ref.orderByKey().equalTo(userId).addValueEventListener(new ValueEventListener() {...}
This way you would retrieve the data of the currently logged in user only.

How to delete data in Recycler view from another acivity

I have One activity in which I am reading JSONData and list in in recycler View.
I have implemented deleting data onLongClick Listener.
On click Listener I am going to Details Activity for that item.
There I have a title, image view button for edit title and button for removing Item.`
The problem is that whether I try to remove or edit title, it does not working when get back to my first Activity.
I think I do not load data in adapter properly at the main activity.
But I do not how to do it better, any solution?
Here is my Main Activity
public class MainActivity extends AppCompatActivity {
FloatingActionButton myFab;
ArrayList<ApiModel> mObjects = new ArrayList<>();
int i = 0;
final String PHOTOS_URL = "http://jsonplaceholder.typicode.com/photos";
List<ApiModel> objects = new ArrayList<>();
private RecyclerView recyclerView;
private MyAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myFab = findViewById(R.id.fab);
myFab.setImageResource(R.drawable.add);
initRecyclerView();
adapter.setData(mObjects);
adapter.notifyDataSetChanged();
//TODO: CHECK WHY NOT WORK DELETE
checkToDeleteOrRename();
adapter.notifyDataSetChanged();
getJsonObjects();
adapter.notifyDataSetChanged();
myFab.setOnClickListener(v -> {
Intent intent = new Intent(MainActivity.this, SendPhoto.class);
startActivity(intent);
});
}
private void checkToDeleteOrRename() {
Intent intentChange = getIntent();
String flag = intentChange.getStringExtra(FLAG_CHANGE);
String flagDelete = intentChange.getStringExtra(FLAG_DELETED);
try {
if (flag.equals(CHANGED)) {
String oldTitle = intentChange.getStringExtra(OLD_TITLE);
String newTitle = intentChange.getStringExtra(NEW_TITLE);
adapter.changeUserName(oldTitle, newTitle);
}
if(flagDelete.equals(DELETED)) {
String userToDelete = intentChange.getStringExtra(USER_DELETED);
adapter.remove(userToDelete);
}
} catch (Exception ex) {
return;
}
}
private void initRecyclerView() {
recyclerView = findViewById(R.id.myRecyclerView);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
adapter = new MyAdapter(this.getApplicationContext());
recyclerView.setAdapter(adapter);
}
public void getJsonObjects() {
AsyncHttpClient client = new AsyncHttpClient();
client.get(PHOTOS_URL, new JsonHttpResponseHandler() {
#Override
public void onSuccess(int statusCode, Header[] headers, JSONArray response) {
objects = fromJson(response);
adapter.notifyDataSetChanged();
}
#Override
public void onFailure(int statusCode, Header[] headers, String responseString, Throwable throwable) {
Toast.makeText(MainActivity.this, "Немате активна Интернет Конекција", Toast.LENGTH_LONG).show();
}
});
}
public ArrayList<ApiModel> fromJson(JSONArray jsonArray) {
try {
for (int i = 0; i < jsonArray.length(); i++) {
try {
JSONObject jsonObject = jsonArray.getJSONObject(i);
ApiModel photoData = new ApiModel();
photoData.mTitle = jsonObject.getString("title");
photoData.Url = jsonObject.getString("url");
photoData.thumbnailUrl = jsonObject.getString("thumbnailUrl");
mObjects.add(photoData);
adapter.notifyDataSetChanged();
} catch (JSONException e1) {
e1.printStackTrace();
}
}
} catch (Exception ex) {
}
return mObjects;
}
}
Here is my delete and edit title methods in Second Activity
public void deleteThis(View view) {
AlertDialog.Builder builder;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
builder = new AlertDialog.Builder(this, android.R.style.Theme_Material_Dialog_Alert);
} else {
builder = new AlertDialog.Builder(this);
}
builder.setTitle("Delete entry")
.setMessage("Are you sure you want to delete this entry?")
.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
Intent deleteIntent = new Intent(SecondActivity.this, MainActivity.class);
deleteIntent.putExtra(FLAG_DELETED, DELETED);
deleteIntent.putExtra(USER_DELETED, mTextView.getText().toString());
mSecondActivity.startActivity(deleteIntent);
Toast.makeText(mSecondActivity, "User deleted", Toast.LENGTH_SHORT).show();
}
})
.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// do nothing
}
})
.setIcon(android.R.drawable.ic_dialog_alert)
.show();
}
public void editTitle(View view) {
DialogFragmentClass dialogFragment = new DialogFragmentClass();
dialogFragment.show(getFragmentManager(),"DIALOG");
}
And here are my methods to remove by title and edit title in my adapter
public void remove(String userName) {
for (ApiModel model: data ) {
if(model.getmTitle() .equals(userName)) {
data.remove(model);
notifyDataSetChanged();
}
}
}
public void changeUserName(String oldUserName, String newUsername){
for (ApiModel model: data ) {
if(model.getmTitle().equals(oldUserName)){
model.setTitle(newUsername);
this.notifyDataSetChanged();
}
}
}

One way to solve your problem is by starting the Second Activity with startActivityForResult and depending upon the action taken by the user on Second Activity put the extras in the intent and call setResult and below that call finish(), then your MainActivity's onActivityResult will get called. Inside onActivityResult you can call your function checkToDeleteOrRename(Intent intent), intent is basically that you receive inside onActivityResult as an argument. Hope this will help you!!!.

you go to another activity by clicking an item in recyclerview
use staractivityforresult to goto another 2ndactivity
also pass positon of item using put extra
and use onactivityforresult inthe 1stctivity that sets the adapter
from 2nd activity if edit or delete done use setresult to pass back edited , delete ,position params using putextra
you will get these value in 1st activity in onactivityresult
using the position, change value in the arraylist accordingly and call notifydatasetchanged

Data fetched from FirebaseDatabase is getting shown in 3 separate AlertDialogs instead of one

I'm fetching some data from FirebaseDatabase and then putting them into an array and then trying to show them in a List which is in a custom AlertDialog.
Here's the code:
query = mDatabase.child("child").child(anotherChild).child("yetAnotherChild");
uProfile.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
query.orderByChild("someChild").addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
if (dataSnapshot != null) {
Map<String, String> newD = (Map<String, String>) dataSnapshot.getValue();
ArrayList<String> l = new ArrayList<String>();
l.add(newD.get("lol").substring(30));
String names[] = l.toArray(new String[0]);
AlertDialog.Builder alertDialog = new AlertDialog.Builder(Activity.this);
LayoutInflater inflater = getLayoutInflater();
View convertView = inflater.inflate(R.layout.dialog_list, null);
alertDialog.setView(convertView);
alertDialog.setTitle("title");
ListView lv = (ListView) convertView.findViewById(R.id.lv);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getBaseContext(), android.R.layout.simple_list_item_1, names);
lv.setAdapter(adapter);
alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
alertDialog.show();
} else {
Toast.makeText(getBaseContext(), "NULLLLL", Toast.LENGTH_SHORT).show();
}
}
...
...
});
}
});
Here's the database structure:
app
-child
-anotherChild
-yetAnotherChild
-inaccessibleChild
-someChild: "value"
-lol: "value"
I can't use valueEventListener() here as I have no access to inaccessibleChild. The inaccessibleChild here is the uid of the other users who followed a particular user. How can I access there uid?
The problem is that data is getting fetched but instead of getting shown in a list in one AlertDialog, it is getting shown one-by-one in 3 separate AlertDialog.
What is going wrong here?
Please let me know.

Firebase transactions are asynchronous so your initial line to add the 3 children happens after you set your listener, therefore your callback is called 3 times. (making 3 dialogs).
Move this line outside of the on click:
query = mDatabase.child("child").child(anotherChild).child("yetAnotherChild");
Then when you add the below listener (inside the on click) it should be ok
query.orderByChild("someChild").addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {

Put limit when you are using valueEventListener or addChildEventListener. like this,
int limit = 100;
databaseRef.child("chats").limitToLast(limit).addValueEventListener(listener);
And always remove listener when you've done with your work related to firebase. like this,
databaseRef.child("chats").limitToLast(limit).removeEventListener(listener);
Thanks.

Create and show the AlertDialog before you call .addChildEventListener()
Then use inside addChildEventListener call notifyDatasetChanged() after you downloaded the appropriate data. Do not create the AlertDialog inside the addChildEventListener

You can use Firebase Queries to limit the data that is downloaded by a listener.
query.orderByChild("someChild").limitToLast(1).addChildEventListener(...

#Blundell has the insight of solving your problem. I just want to suggest you a similar approach with addValueEventListener.
The value event listener will fire once for the initial state of the
data, and then again every time the value of that data changes.
You need to move out the firebase query from onClick function. So your query might look like this..
// Declare the variable names as public
private String names[];
private void addFirebaseListener() {
ref = mDatabase.child("child").child(anotherChild).child("yetAnotherChild");
ref. userRef.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot snapshot) {
Map<String, String> newD = (Map<String, String>) dataSnapshot.getValue();
ArrayList<String> l = new ArrayList<String>();
l.add(newD.get("lol").substring(30));
names[] = l.toArray(new String[0]);
// Call notifyDataSetChanged each time your array gets updated
adapter.notifyDataSetChanged();
}
#Override public void onCancelled(FirebaseError error) { }
});
}
Now write a function to show the ListView in the AlertDialog
// Declare the adapter as public and initialize it with null
private ArrayAdapter<String> adapter = null;
private void showListInDialog() {
AlertDialog.Builder alertDialog = new AlertDialog.Builder(Activity.this);
LayoutInflater inflater = getLayoutInflater();
View convertView = inflater.inflate(R.layout.dialog_list, null);
alertDialog.setView(convertView);
alertDialog.setTitle("title");
ListView lv = (ListView) convertView.findViewById(R.id.lv);
if(adapter == null)
adapter = new ArrayAdapter<String>(getBaseContext(), android.R.layout.simple_list_item_1, names);
// Now set the adapter
lv.setAdapter(adapter);
alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
alertDialog.dismiss();
}
});
alertDialog.show();
}
Now inside your onCreate function you need to set the Firebase listener first and then set the onClick function like this.
uProfile.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
showListInDialog();
}
});

#Hammad Try this modified code basing on your requirement.
query = mDatabase.child("child").child(anotherChild).child("yetAnotherChild");
AlertDialog alertDialog;
ArrayList<String> l;
uProfile.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
query.orderByChild("someChild").addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
if (dataSnapshot != null) {
Map<String, String> newD = (Map<String, String>) dataSnapshot.getValue();
if(l == null) {
l = new ArrayList<String>();
}
l.add(newD.get("lol").substring(30));
String names[] = new String[l.size()];
for(int length=0; length < l.size(); l++) {
names[length] = l.get(length);
}
if(alertDialog == null) {
alertDialog = new AlertDialog.Builder(Activity.this).create();
LayoutInflater inflater = getLayoutInflater();
View convertView = inflater.inflate(R.layout.dialog_list, null);
alertDialog.setView(convertView);
alertDialog.setTitle("title");
ListView lv = (ListView) convertView.findViewById(R.id.lv);
} ArrayAdapter<String> adapter = new ArrayAdapter<String>(getBaseContext(), android.R.layout.simple_list_item_1, names);
lv.setAdapter(adapter);
alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
if(!alertDialog.isShowing()) {
alertDialog.show();
}
} else {
Toast.makeText(getBaseContext(), "NULLLLL", Toast.LENGTH_SHORT).show();
}
}
...
...
});
}
});

ChildEventListener childEventListener = new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {
Log.d(TAG, "onChildAdded:" + dataSnapshot.getKey());
/**
Retrieve lists of items or listen for additions to a list of items. This callback is triggered once for each existing child and then again every time a new child is added to the specified path. The DataSnapshot passed to the listener contains the new child's data.
**/
}
#Override
public void onChildChanged(DataSnapshot dataSnapshot, String previousChildName) {
Log.d(TAG, "onChildChanged:" + dataSnapshot.getKey());
}
#Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
Log.d(TAG, "onChildRemoved:" + dataSnapshot.getKey());
}
#Override
public void onChildMoved(DataSnapshot dataSnapshot, String previousChildName) {
Log.d(TAG, "onChildMoved:" + dataSnapshot.getKey());
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
};
ref.addChildEventListener(childEventListener);
Usining ChildEventListener onChildAdded are call per child you have in that node. Means your code runs 3 time so dialog appers 3 time.
This is the problem
So the solution is:
While using a ChildEventListener is the recommended way to read lists of data, there are situations where attaching a ValueEventListener to a list reference is useful.
Attaching a ValueEventListener to a list of data will return the entire list of data as a single DataSnapshot, which you can then loop over to access individual children.
Even when there is only a single match for the query, the snapshot is still a list; it just contains a single item. To access the item, you need to loop over the result:
inaccessibleChild.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
//here you can access the each child of that node.
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
// Getting Post failed, log a message
Log.w(TAG, "loadPost:onCancelled", databaseError.toException());
// ...
}
});

Well, none of the above answers really helped, though Linxy's answer is correct, I saw it after solving the probelm.
Moving all the code out and writing just this line: alertDialog.show(); inside setOnClickListener() improving my code to this:
query = mDatabase.child("child").child(anotherChild).child("yetAnotherChild");
query.orderByChild("someChild").addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
if (dataSnapshot != null) {
Map<String, String> newD = (Map<String, String>) dataSnapshot.getValue();
ArrayList<String> l = new ArrayList<String>();
l.add(newD.get("lol").substring(30));
String names[] = l.toArray(new String[0]);
AlertDialog.Builder alertDialog = new AlertDialog.Builder(Activity.this);
LayoutInflater inflater = getLayoutInflater();
View convertView = inflater.inflate(R.layout.dialog_list, null);
alertDialog.setView(convertView);
alertDialog.setTitle("title");
ListView lv = (ListView) convertView.findViewById(R.id.lv);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getBaseContext(), android.R.layout.simple_list_item_1, names);
lv.setAdapter(adapter);
alertDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
} else {
Toast.makeText(getBaseContext(), "NULLLLL", Toast.LENGTH_SHORT).show();
}
}
...
...
});
uProfile.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
alert11.show();
}
});
Anyway, I would like to thank all those who answered this question.
Peace.