class MainAdapter : PagedListAdapter<ItemViewModel, MainAdapter.ItemViewHolder>(ItemCallback) {

    override fun getItemViewType(position: Int): Int {
        return when (getItem(position)) {
            is BannerView.Model -> 1
            // bla bla
            else -> 0 // loading model
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ItemViewHolder {
        val inflater = LayoutInflater.from(parent.context)
        val layoutRes = when (viewType) {
            1 -> R.layout.banner_view
            // bla bla
            else -> R.layout.loading_view
        }
        val view = inflater.inflate(layoutRes, parent, false)
        return ItemViewHolder(view = view)
    }

    override fun onBindViewHolder(holder: ItemViewHolder, position: Int) {
        val model = getItem(position) ?: LoadingView.Model(
            id = "loading $position"
        )

        when (model) {
            is BannerView.Model -> (holder.itemView as BannerView).apply {
                setContent(model.content)
                setOnClick(model.onClick)
            }
            // bla bla
        }
    }


    class ItemViewHolder(view: View) : RecyclerView.ViewHolder(view)
}