sergei-lapin

class DragGestureDetector(private val onDragListener: OnDragListener) {

    var posX = 0f
        private set
    var posY = 0f
        private set

    private var activePointerId = -1

    fun onTouchEvent(event: MotionEvent): Boolean {

sergei-lapin

class RotateGestureDetector(private val onRotateListener: OnRotateListener) {

    val rotationDeltaDegrees: Float
        get() {
            val diffRadians = atan2(prevDiffY, prevDiffX) - atan2(currDiffY, currDiffX)
            return Math.toDegrees(diffRadians.toDouble()).toFloat()
        }

    var focusX = 0f
        private set

sergei-lapin

internal fun onItemCreatedOutside(viewType: Int) {
    itemsCreated[viewType] = itemsCreated.getOrZero(viewType) + 1
}

sergei-lapin

typealias ViewHolderProducer = (parent: ViewGroup, viewType: Int) -> RecyclerView.ViewHolder

sergei-lapin

protected fun createItem(viewType: Int) {
    val created = itemsCreated.getOrZero(viewType) + 1
    val queued = itemsQueued.getOrZero(viewType)
    if (created > queued) return

    val holder: RecyclerView.ViewHolder
    val start: Long
    val end: Long

    try {

sergei-lapin

internal fun setPrefetchBound(viewType: Int, count: Int) {
    if (itemsQueued.getOrZero(viewType) >= count) return
    itemsQueued[viewType] = count

    val created = itemsCreated.getOrZero(viewType)
    if (created >= count) return

    repeat(count - created) { enqueueItemCreation(viewType) }
}

sergei-lapin

typealias ViewHolderProducer = (parent: ViewGroup, viewType: Int) -> RecyclerView.ViewHolder
typealias ViewHolderConsumer = (viewHolder: RecyclerView.ViewHolder, creationTimeNanos: Long) -> Unit


abstract class ViewHolderSupplier(
    context: Context,
    private val viewHolderProducer: ViewHolderProducer
) {

    internal lateinit var viewHolderConsumer: ViewHolderConsumer

sergei-lapin

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

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

sergei-lapin

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

sergei-lapin

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