populateViewHolder没有使用FirebaseRecyclerAdapter

Question

我的主要问题是永远不会调用populateViewHolder方法。 我检查了这个populateViewHolder方法是否由Log激活。 为什么不执行这个populateViewHolder方法？

我添加了这个依赖词

   compile 'com.firebaseui:firebase-ui-database:1.2.0'

这是我的代码

Query conversationQuery = mConvDatabase.orderByChild("timestamp");
    FirebaseRecyclerAdapter<Conv, ConvViewHolder> firebaseConvAdapter = new FirebaseRecyclerAdapter<Conv, ConvViewHolder>(
            Conv.class,
            R.layout.users_single_layout,
            ConvViewHolder.class,
            conversationQuery
    ) {

        @Override
        protected void populateViewHolder(final ConvViewHolder convViewHolder, final Conv conv, int i) {
            Log.d("success","response");