createChild method
override
Copied from SliverMultiBoxAdaptorElement.createChild.
Implementation
@override
void createChild(final int index, {@required final RenderBox after}) {
assert(_currentlyUpdatingChildIndex == null);
owner.buildScope(this, () {
final insertFirst = after == null;
assert(insertFirst || _childElements[index - 1] != null);
_currentBeforeChild = insertFirst
? null
: (_childElements[index - 1].renderObject as RenderBox);
Element newChild;
try {
_currentlyUpdatingChildIndex = index;
newChild = updateChild(_childElements[index], _build(index), index);
} finally {
_currentlyUpdatingChildIndex = null;
}
if (newChild != null) {
_childElements[index] = newChild;
} else {
_childElements.remove(index);
}
});
}