Вы можете сделать это, используя стек и анимацию:
class HelloWorldPage extends StatefulWidget {
@override
_HelloWorldPageState createState() => _HelloWorldPageState();
}
class _HelloWorldPageState extends State<HelloWorldPage>
with SingleTickerProviderStateMixin {
final double minSize = 80;
final double maxSize = 350;
void initState() {
_controller =
AnimationController(vsync: this, duration: Duration(milliseconds: 500))
..addListener(() {
setState(() {});
});
_animation =
Tween<double>(begin: minSize, end: maxSize).animate(_controller);
super.initState();
}
AnimationController _controller;
Animation<double> _animation;
@override
Widget build(BuildContext context) {
return Scaffold(
body: Stack(
fit: StackFit.expand,
children: <Widget>[
Positioned(
bottom: 0,
height: _animation.value,
child: GestureDetector(
onDoubleTap: () => _onEvent(),
onVerticalDragEnd: (event) => _onEvent(),
child: Container(
color: Colors.red,
width: MediaQuery.of(context).size.width,
height: minSize,
),
),
),
],
),
);
}
_onEvent() {
if (_controller.isCompleted) {
_controller.reverse(from: maxSize);
} else {
_controller.forward();
}
}
@override
void dispose() {
_controller.dispose();
super.dispose();
}
}