setActiveChildIndex method

Implementation

void setActiveChildIndex(int idx) {
  if (children != null) {
    _activeChildIndex = min(children!.length, max(0, idx));
    for (int i = 0; i < children!.length; i++) {
      var child = children![i];
      bool cv = i != (_activeChildIndex - 1);
      if (child is ActorNode) {
        child.collapsedVisibility = cv; // Setter
      }
    }
  }
}