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I have this code:

DocumentReference documentReference = fStore.collection("Studenti").document(userID);
    documentReference.addSnapshotListener(this, new EventListener<DocumentSnapshot>() {

        @Override
        public void onEvent(@Nullable DocumentSnapshot documentSnapshot, @Nullable FirebaseFirestoreException e) {

            View header = navigationView.getHeaderView(0);
            TextView text = header.findViewById(R.id.nume_elev);

            //text.setText(documentSnapshot.getString("nume"));
            //String mail = documentSnapshot.getString("email");

            spec = documentSnapshot.getString("specializare"); // it gets the value from firebase


        }
    });


    //Query
    Query qexamene = fStore.collection("/Examene/an1/sem1").whereEqualTo("specializare", spec);

How can I use 'spec' or the "documentSnapshot.getString" outside of onEvent method?

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  • 2
    Store it in a member variable or global, and make sure the other code doesn't execute until after the callback is invoked asynchronously. Or, pass the data along to a method that you invoke from within the callback. Commented Jul 5, 2020 at 21:27
  • can you please go into a bit more detail or point me to a place where I could understand this? I'm new to android studio and programming in general. Commented Jul 5, 2020 at 21:31
  • I tried to have 'spec' as a String var but it doesn't help, when it gets out of onEvent it loses the value assigned in the onEvent method. I don't know how to code to use it in the line below. Commented Jul 5, 2020 at 21:34
  • That's because addSnapshotListener is asynchronous, and the callback you provide will be invoked some time later, after the query completes. You will need to use the callback to continue your work. Commented Jul 5, 2020 at 21:38
  • All code that needs the data from the database, needs to be inside onEvent or be called from there. I added some links to previous questions covering the same. This one specifically deals with nested queries: stackoverflow.com/questions/61542953/… Commented Jul 5, 2020 at 21:49
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