expandNode method
Expands the given node
so its children become visible.
This will change the node
NodeViewModelState.isCollapsed property to
false. But its children won't change states, so when the node is expanded
its children states are unchanged.
notifyListeners is called to notify all registered listeners.
See also:
Implementation
void expandNode(NodeViewModelState node) {
if (!node.isCollapsed || !node.isRoot) {
return;
}
final nodeIndex = _displayNodes.indexOf(node) + 1;
final nodes = flatten(node.value);
_displayNodes.insertAll(nodeIndex, nodes);
node.expand();
notifyListeners();
}