查询数据库Firebase Firestore

我想在Firestore中查询数据并将查询数据保存到领域,但总是出错。我认为问题是我在创建领域对象之后得到了查询结果。任何人都知道如何处理这个问题,我不知道如何解决这个问题。

这是我的密码

    collectionReference = db.collection("Lookup");
    Query query = collectionReference.whereEqualTo("email", email );

    Log.d("Initial Lookup: ", "begin");
    Log.d("Initial Lookup: ", email);

    query.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {
            Log.d("Doc Snapshot: ", "Complete Query!");
            if(task.isSuccessful()){
                Log.d("Doc Snapshot: ", "Success Query!");
                int i = 0;
                for(QueryDocumentSnapshot doc: task.getResult()){
                    Log.d("Doc Snapshot: ", "-----------------------");
                    Log.d("Doc Snapshot: ", "" + doc.getData());
                    i++;

                    Realm realm = Realm.getDefaultInstance();

                    realm.beginTransaction();
                    LookupModel model = realm.createObject(LookupModel.class);
                    model.setEmail(email);
                    model.setId(String.valueOf(doc.getData().get("id")) );
                    Log.d("id", String.valueOf(doc.getData().get("id")) );
                    model.setSimkey(Simkey);
                    Log.d("key", Simkey);
                    realm.commitTransaction();
                }
                Log.d("Document Query Count: ", "" + i);
            } else{
                Log.d("Error Snapshot: ", String.valueOf(task.getException()) );
            }
        }

    });
    realm = Realm.getDefaultInstance();
    LookupModel mod = realm.where(LookupModel.class)
            .equalTo("simkey", key)
            .findFirst();
    String id = mod.getId();

String id = mod.getId();