move method
Implementation
void move(int index) {
if (_sliverListController == null) {
return;
}
moveIndex = index;
var offsetCenter = _sliverListController!
.getItemOffset(index, AntdEdge.center, AntdEdge.center);
var offset = _sliverListController!.getWindowOffset(
index: index, viewportAlign: AntdEdge.start, offset: offsetCenter ?? 0);
if (offset == null) {
return;
}
double newPosition = offset + getIndicatorOffset(index);
moveOffset(newPosition);
}