Checking Firestore Collection element exist or not-CodePudding

I want to check the entered text (EditText) element is exist or not using Firestore Collection if Exists where exists or fetch the remain elements Note: we don't have document id

I want to mobile if our user collection the mobile exists then fetch the remain elements the document id will Random using AutoID and ignore Additional Collections like Withdraw Requests

I write this code in my activity

private void fetchDatafromFirestoreCollection() {

    firestore.collection("Users").addSnapshotListener(new EventListener<QuerySnapshot>() {
        @Override
        public void onEvent(@Nullable QuerySnapshot value, @Nullable FirebaseFirestoreException error) {
            if (error != null) {
                if (dialog.isShowing())
                    dialog.dismiss();

                Log.e(TAG, "Error is: ", error);
                return;

            }
            for (DocumentChange documentChange : value.getDocumentChanges())
        }
    });

}

CodePudding user response：

According to this comment:

I want to to check in Users collection is ReferCode "ABC123" exists if exists who is the user then I fetch the mobile or other details

And this comment:

I want to fetch all the documents to check where ABC123 exists or not to give him refferal amount.

To solve this, you have to use a query that looks like this:

FirebaseFirestore db = FirebaseFirestore.getInstance();
CollectionReference usersRef = db.collection("Users");
usersRef.whereEqualTo("ReferCode", "ABC123").get()
    .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {
            if (task.isSuccessful()) {
                for (QueryDocumentSnapshot document : task.getResult()) {
                    String mobile = document.getString("Mobile");
                    Log.d("TAG", mobile);

                    //Do what you need to do with the phone number
                }
            } else {
                Log.d(TAG, "Error getting documents: ", task.getException());
            }
        }
    });

The result in the logcat will be:

9876543210

CodePudding user response：

Make the document structure like this one:

    DocumentReference docRef = db.collection("Users").document("123456789");
                docRef.addSnapshotListener(new EventListener<DocumentSnapshot>() {
                    @Override
                    public void onEvent(DocumentSnapshot snap, FirestoreException fe) {
                        if (snap.exists()) {
                            //exists
                        for (DocumentChange dc : snap.getDocumentChanges()) {
                            //Store exist information to your Object model.
                            UserInfo userinfo = dc.getDocument().toObject(UserInfo.class);
                         Log.e(TAG, "userinfo: " userinfo.getCompany);
                        }
                        } else {
                            //not exists
                        }
                    }
    
                });

Hope its work..