FirebaseUI-Android を使用して RecyclerView 項目 ViewHolders でイベント リスナーを管理する方法

<code class="java">@Override
protected void populateViewHolder(final ConvViewHolder convViewHolder, final Conv conv, int i) {

    final String list_user_id = getRef(i).getKey();

    final DocumentReference docRef = db.collection("cities").document(list_user_id);
    // Add a listener to the document reference
    EventListener<DocumentSnapshot> eventListener = new EventListener<DocumentSnapshot>() {
        @Override
        public void onEvent(@Nullable DocumentSnapshot snapshot,
                            @Nullable FirebaseFirestoreException e) {
            if (e != null) {
                Log.w(TAG, "Listen failed.", e);
                return;
            }

            if (snapshot != null && snapshot.exists()) {
                Log.d(TAG, "Current data: " + snapshot.getData());
            } else {
                Log.d(TAG, "Current data: null");
            }
        }
    };
    docRef.addSnapshotListener(eventListener);
}</code>

<code class="java">// Inside your RecyclerView adapter
private ListenerRegistration listenerRegistration;

if (listenerRegistration == null) {
    listenerRegistration = yourRef.addSnapshotListener(eventListener);
}</code>

<code class="java">@Override
protected void onStop() {
    if (listenerRegistration != null) {
        listenerRegistration.remove();
    }
}</code>