getItemSizesFromSliverList method
_SizeResult?
getItemSizesFromSliverList(
- int buildFrom,
- int buildTo
)
Implementation
_SizeResult? getItemSizesFromSliverList(int buildFrom, int buildTo) {
assert(!intervalManager.hasPendingUpdates);
if (firstChild == null) return null;
var listFrom = indexOf(firstChild!);
var listTo = indexOf(lastChild!) + 1;
if (buildTo <= listFrom || buildFrom >= listTo) return null;
var from = math.max(listFrom, buildFrom);
var to = math.min(listTo, buildTo);
if (to <= from) return null;
var child = firstChild;
for (var i = listFrom; i < from; i++) {
child = childAfter(child!);
}
var size = 0.0;
for (var i = from; i < to; i++) {
size += paintExtentOf(child!);
child = childAfter(child);
}
return _SizeResult(from, to, size);
}