Collapsible

class CollapsiblePage extends StatefulWidget {
  @override
  State<CollapsiblePage> createState() => _CollapsiblePageState();
}
 
class _CollapsiblePageState extends State<CollapsiblePage> with SingleTickerProviderStateMixin {
  late final _controller = AnimationController(duration: const Duration(milliseconds: 300), vsync: this);
  late final _animation = CurvedAnimation(parent: _controller, curve: Curves.easeInOut);
  bool _expanded = false;
 
  @override
  void dispose() {
    _animation.dispose();
    _controller.dispose();
    super.dispose();
  }
 
  @override
  Widget build(BuildContext context) => Column(
    mainAxisSize: MainAxisSize.min,
    crossAxisAlignment: CrossAxisAlignment.start,
    spacing: 16,
    children: [
      FButton(
        onPress: () {
          setState(() => _expanded = !_expanded);
          _controller.toggle();
        },
        child: Text(_expanded ? 'Collapse' : 'Expand'),
      ),
      AnimatedBuilder(
        animation: _animation,
        builder: (context, child) => FCollapsible(
          value: _animation.value,
          child: FCard(
            title: const Text('Lorem ipsum'),
            child: const Text(
              'Sed ut perspiciatis unde omnis iste natus error sit voluptatem '
              'accusantium doloremque laudantium, totam rem aperiam, eaque ipsa '
              'quae ab illo inventore veritatis et quasi architecto beatae vitae '
              'dicta sunt explicabo.',
            ),
          ),
        ),
      ),
    ],
  );
}