Heigh Change Tween Animation Issue in Flutter - flutter

Question

I want to animate the Height of My container
What I am try to do is :
class _AddVehicleState extends State<AddVehicle>
with SingleTickerProviderStateMixin {
AnimationController _otherFieldsAnimationController;
Animation<double> _heightAnimation;
override
void initState() {
_otherFieldsAnimationController = AnimationController(
vsync: this,
duration: const Duration(milliseconds: 3000),
);
_heightAnimation = new Tween<double>(begin: 400.0, end: 20.0)
.animate(_otherFieldsAnimationController);
_otherFieldsAnimationController.forward();
}
#override
Widget build(BuildContext context) {
return new WillPopScope(
onWillPop: _onWillPop,
child: new Scaffold(body: Builder(builder: (scaffoldContext1) {
scaffoldContext = scaffoldContext1;
return Stack(
children: <Widget>[
new Container(
decoration: getGradientBackground(),
child: ListView(
children: <Widget>[
Container(
color: Colors.white70,
height: _heightAnimation.value,
child: Center(
child: Text('HEY'),
));
.
.
.
.
.
As you can see the container contains the height of Animation.
All the other animation on this page works perfectly but this container is not being animated.
Any particular reason? Or am I missing something?

Answer 1

You can use the animated container like this
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> with SingleTickerProviderStateMixin {
AnimationController _controller;
Animation<double> _animation;
var _duration = const Duration(milliseconds: 3000);
#override
void initState() {
super.initState();
_controller = AnimationController(
vsync: this,
duration: _duration,
)..addListener(() {
setState(() {});
});
_animation =
new Tween<double>(begin: 20.0, end: 400.0).animate(_controller);
_controller.forward();
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Stackoverflow'),
),
body: Center(
child: AnimatedContainer(
duration: _duration,
height: _animation.value,
width: 200,
color: Colors.amber,
),
));
}
}