How to query an array list in a Firebase document?

Question

I'm trying to query my database for an android application, if a username is in the 'fave' array field of my database and if so then change the background of an image. My database is set up like this...

I don't know if i'm doing it right but currently i think i may be checking the whole collection rather than a specific document and it's not even returning anything. Any suggestions would be appreciated!

Answer 1

You wanted this?

FirebaseFirestore.getInstance().collection("Trainers").document("Air Force 1 Low").get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
    @Override
    public void onSuccess(DocumentSnapshot documentSnapshot) {
        List<String> list = (List<String>)documentSnapshot.get("fave");
        for (String name : list){
            if (name.equals("Admin")){
                //do if user is admin
                return;
            }
        }
        //do if user is not admin
    }
});