Flutter animations - How to trigger OpenContainer programmatically?

Question

I make use of the flutter animations package: https://pub.dev/packages/animations

I am trying to open the container automatically after 3 seconds in my initState function. Is there any way to trigger the container programmatically? I can not find any implementation of a controller or something...

@override
  Widget build(BuildContext context) { 

    OpenContainer(
                transitionDuration: Duration(milliseconds: 400),
                transitionType: _transitionType,
                openBuilder: (BuildContext context, VoidCallback _) {
                  return AddRouteParent();
                },
                closedElevation: 6.0,
                closedShape: const RoundedRectangleBorder(
                  borderRadius: BorderRadius.all(
                    Radius.circular(_fabDimension / 2),
                  ),
                ),
                closedColor: Color(0xff17c387),
                closedBuilder:
                    (BuildContext context, VoidCallback openContainer) {
                  return Showcase(
                    shapeBorder: CircleBorder(),
                    radius: BorderRadius.all(Radius.circular(30)),
                    overlayPadding: EdgeInsets.all(5),
                    key: _five,
                    description:
                        'Hier kannst du dir deine\neigene Route erstellen.',
                    child: SizedBox(
                      height: _fabDimension,
                      child: Padding(
                        padding: const EdgeInsets.fromLTRB(12, 0, 20, 0),
                        child: Row(mainAxisSize: MainAxisSize.min, children: [
                          Icon(
                            Icons.add,
                            color: Colors.white,
                          ),
                          SizedBox(width: 12),
                          Text("Erstellen",
                              style:
                                  TextStyle(color:     Colors.white, fontSize: 18))
                        ]),
                      ),
                    ),
                  );
                });
  }

Answer 1

Solved this a while ago, just store the action parameter from the closedBuilder like this:

closedBuilder: (BuildContext context, void Function() action) {
                  _openContainer = action;

Then call it anywhere else like this: _openContainer.call();