AsyncListUtil.ViewCallback

const val HINT_SCROLL_ASC = 2: Int

Scrolling in ascending order (from lower to higher positions in the order of the backing storage).

const val HINT_SCROLL_DESC = 1: Int

Scrolling in descending order (from higher to lower positions in the order of the backing storage).

const val HINT_SCROLL_NONE = 0: Int

No scroll direction hint available.

@UiThread
fun extendRangeInto(range: IntArray, outRange: IntArray, scrollHint: Int): Unit

Compute a wider range of items that will be loaded for smoother scrolling.

If there is no scroll hint, the default implementation extends the visible range by half its length in both directions. If there is a scroll hint, the range is extended by its full length in the scroll direction, and by half in the other direction.

For example, if range is {100, 200} and scrollHint is HINT_SCROLL_ASC, then outRange will be {50, 300}.

However, if scrollHint is HINT_SCROLL_NONE, then outRange will be {50, 250}

@UiThread
abstract fun getItemRangeInto(outRange: IntArray): Unit

Compute the range of visible item positions.

outRange[0] is the position of the first visible item (in the order of the backing storage).

outRange[1] is the position of the last visible item (in the order of the backing storage).

Negative positions and positions greater or equal to getItemCount are invalid. If the returned range contains invalid positions it is ignored (no item will be loaded).

@UiThread
abstract fun onDataRefresh(): Unit

Called when the entire data set has changed.

@UiThread
abstract fun onItemLoaded(position: Int): Unit

Called when an item at the given position is loaded.