Firebase Cloud Firestore遵循参考

Question

我已使用以下代码获得queryDocumentSnapshot：

mFireStore = FirbaseFirestore.getInstance();
mFireStore.collection("myCollection").addSnapshotListener(new EventListener<QuerySnapshot>() {
            @Override
            public void onEvent(@Nullable QuerySnapshot queryDocumentSnapshots, @Nullable FirebaseFirestoreException e) {
                for (DocumentChange doc : queryDocumentSnapshots.getDocumentChanges()) {
                    if (doc.getType() == DocumentChange.Type.ADDED) {
                        // Set some data from the doc.getDocument here

mFireStore.collection("myCollection").document(doc.getDocument().getId()).collection("subCollection").get().addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
                                    @Override
                                    public void onSuccess(QuerySnapshot queryDocumentSnapshots) {
                                        if (queryDocumentSnapshots.isEmpty()){
                                            // not found
                                        } else{

                                            List<DocumentSnapshot> hosts = queryDocumentSnapshots.getDocuments();

                                            for (int i = 0; i < hosts.size(); i++){
                                                // Each hosts DocumentSnapshot has a "host" field which contains a reference to a document
                                                // I'd like to follow this reference and get that document
                                            }
                                        }
                                    }
                                });

我的问题是，一旦我获得了主持人DocumentSnapshots的列表，我就想关注他们的主持人＆＃34;包含对文档的引用的字段。我想按照这个参考，在另一端得到文件，但不知道如何。如果您发现我的逻辑存在任何其他问题，请随意指出，因为我对Cloud Firestore不熟悉。