Full Consumer code

PrefetchViewPool.kt

class PrefetchViewPool(
    private val defaultMaxRecycledViews: Int,
    private val viewHolderSupplier: ViewHolderSupplier
) : RecyclerView.RecycledViewPool() {

    private val recycledViewsBounds = mutableMapOf<Int, Int>()

    init {
        attachToPreventFromClearing()
        viewHolderSupplier.viewHolderConsumer = ::putViewFromSupplier
        viewHolderSupplier.start()
    }

    fun setPrefetchBound(viewType: Int, count: Int) {
        recycledViewsBounds[viewType] = max(defaultMaxRecycledViews, count)
        viewHolderSupplier.setPrefetchBound(viewType, count)
    }

    override fun putRecycledView(scrap: RecyclerView.ViewHolder) {
        val viewType = scrap.itemViewType
        val maxRecycledViews = recycledViewsBounds.getOrPut(viewType) { defaultMaxRecycledViews }
        setMaxRecycledViews(viewType, maxRecycledViews)
        super.putRecycledView(scrap)
    }

    override fun getRecycledView(viewType: Int): RecyclerView.ViewHolder? {
        val holder = super.getRecycledView(viewType)
        if (holder == null) viewHolderSupplier.onItemCreatedOutside(viewType)
        return holder
    }

    override fun clear() {
        super.clear()
        viewHolderSupplier.stop()
    }

    private fun putViewFromSupplier(scrap: RecyclerView.ViewHolder, creationTimeNanos: Long) {
        factorInCreateTime(scrap.itemViewType, creationTimeNanos)
        putRecycledView(scrap)
    }
}