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

Question

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.

Answer 1

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) {

Answer 2

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.