withExpandAll method Null safety

TreeViewController withExpandAll(
  1. {Node? parent}
)

Expands all nodes down to parent Node. It returns a new controller with the nodes expanded. This method expects the user to properly place this call so that the state is updated.

Internally uses TreeViewController.expandAll.

setState((){
  controller = controller.withExpandAll();
});

Implementation

TreeViewController withExpandAll({Node? parent}) {
  List<Node> _data = expandAll(parent: parent);
  return TreeViewController(
    children: _data,
    selectedKey: this.selectedKey,
  );
}