Activity：

      //在子线程中进行预加载
                    preloadCacheViewsInThread(beanList) {
                        //预加载完毕，回到主线程处理UI
                        runOnUiThread {
                            handleRefreshSuccess(beanList)
                        }
                    }

private fun preloadCacheViewsInThread(topicBeanList: MutableList<TopicBean>, success: () -> Unit) {
        Thread {
            var pictureCountInFirstPage = 0 //第一页有多少个图片
            var commentCountInFirstPage = 0 //第一页有多少条小评论
            var nowTime = System.currentTimeMillis()
            for (topicBean in topicBeanList){
                topicBean.findTotalSpanText(this@FriendActivity2, this@FriendActivity2)
                topicBean.pictures?.let { pictureCountInFirstPage += it.count() }
            }
            Log.e(
                "dq",
                "预处理Model耗时为：" + (System.currentTimeMillis() - nowTime) + "毫秒"
            ) //方法运行时间为：12毫秒

            val layoutInflater = LayoutInflater.from(this@FriendActivity2)

            //开始预加载每个Item的xml布局
            nowTime = System.currentTimeMillis()
            var i = 0
            while (i < 8 && i < topicBeanList.count()) {
                //这个8是预估的数字，也就是屏幕中的 + mCacheView（size == 2）+ pool里的（max是5，一般就是1）
                val itemView: View = layoutInflater.inflate(R.layout.listitem_topic, null)
               //缓存起来，放到onCreateHolder中使用
                cachedItemViewList!!.add(itemView)
                i++
            }
            Log.e(
                "dq",
                "预加载耗时为：" + (System.currentTimeMillis() - nowTime) + "毫秒"
            ) //方法运行时间为：150毫秒


            //开始预加载每个Item中的图片的imageview
            i = 0
            while (i < 10 && i < pictureCountInFirstPage) {
                val pictureImageView = ImageView(this@FriendActivity2)
                cachedImageViewList.add(pictureImageView)
                i++
            }
            Log.e(
                "dq",
                "预Image和Text耗时为：" + (System.currentTimeMillis() - nowTime) + "毫秒"
            ) //方法运行时间为：120毫秒

            success()

        }.start()
    }

Adpater:

//创建ViewHolder并绑定上itemview
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
            var view: View? = null
            cachedItemViewList?.let {
                view = it.poll()
                Log.e("dq", "onCreateViewHolder = 用上缓存")
            }
            if (view == null){
                view = mInflater.inflate(R.layout.listitem_topic, parent, false)
                Log.e("dq", "onCreateViewHolder = 没用上缓存")
            }
            val viewHolder = TopicViewHolder(view!!)

            if (this::cachedImageViewList.isInitialized) {
                //是用了预加载
                viewHolder.pictureGridLayout.cachedImageViewList = cachedImageViewList
                viewHolder.linearLayoutForListView.cachedTextViewList = cachedTextViewList
            }

            return viewHolder
    }


    override fun onViewRecycled(holder: RecyclerView.ViewHolder) {
        if (holder is TopicViewHolder) {
            for (view in holder.pictureGridLayout.children) {
                if (view is ImageView){
                    //必须要移除，不然会：You must call removeView()
                    cachedImageViewList.add(view);
                    view.setImageDrawable(null)
                    Log.e("dq","缓冲池回收图片 " + cachedImageViewList.size);
                }
            }
            holder.pictureGridLayout.removeAllViews()

            for (view in holder.linearLayoutForListView.children) {
                if (view is QMUILinkTextView){
                    //必须要移除，不然会：The specified child already has a parent. You must call removeView()
                    cachedTextViewList.add(view);
                    Log.e("dq","缓冲池回收评论 " + cachedTextViewList.size);
                }
            }
            //必须要移除，不然会： You must call removeView()
            holder.linearLayoutForListView.removeAllViews()
        }
    }