addChildAt method
Adds a child DisplayObject to this DisplayObjectContainer at the
specified index
position.
An index
of 0 represents the back (bottom) of the display list for this
DisplayObjectContainer.
If you add a child object that already has a different display object container as a parent, the object is removed from the child list of the other display object container.
Implementation
@override
void addChildAt(DisplayObject child, int index) {
if (index < 0 || index > _children.length) {
throw ArgumentError('The supplied index is out of bounds.');
} else if (child == this) {
throw ArgumentError('An object cannot be added as a child of itself.');
} else if (child.parent == this) {
_addLocalChildAt(child, index);
} else {
child.removeFromParent();
_throwIfAncestors(child);
_children.insert(index, child);
_setChildParent(child);
}
}