Flutter Web Unexpectedly null value after call Hot Reload - dart

Question

We are developing a large project with flutter web. But when we run the application in debug mode, it works fine at first, but when we make a change and hot reload/hot restart, we get an Unexpected null value error. When we build our web application again, it continues to work without any problems.
Error Message:
The following TypeErrorImpl was thrown building AnimatedBuilder(animation:
AnimationController#6e18e(⏮ 0.000; paused), dirty, dependencies: [MediaQuery], state:
_AnimatedState#b099a):
Unexpected null value.
The relevant error-causing widget was:
AnimatedBuilder
AnimatedBuilder:file:///Users/taner/Documents/GitHub/kinderbox_web/lib/view/admin/page_controller/web/page_controller_web.dart:51:15
page_controller_web.dart file:
import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'package:kinderbox_web/core/constant/color_constant.dart';
import 'package:kinderbox_web/core/providers/page_controller_provider.dart';
import 'package:kinderbox_web/core/providers/user_provider.dart';
import 'package:kinderbox_web/widgets/admin/drawer/web/drawer_bar.dart';
import 'package:kinderbox_web/widgets/admin/header/web/header_web.dart';
class PageControllerWeb extends StatefulWidget {
final List<Widget> pages;
const PageControllerWeb({
Key? key,
required this.pages,
}) : super(key: key);
#override
State<PageControllerWeb> createState() => _PageControllerWebState();
}
class _PageControllerWebState extends State<PageControllerWeb>
with SingleTickerProviderStateMixin {
double maxWidth = 300;
double minWidth = 70;
bool isCollapsed = false;
late AnimationController _animationController;
late Animation<double> widthAnimation;
int currentIndex = 0;
#override
void dispose() {
_animationController.dispose();
super.dispose();
}
#override
void initState() {
_animationController =
AnimationController(vsync: this, duration: Duration(milliseconds: 300));
widthAnimation = Tween<double>(begin: maxWidth, end: minWidth)
.animate(_animationController);
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold(
backgroundColor: ColorConstants.background,
body: AnimatedBuilder(
animation: _animationController,
builder: (BuildContext context, Widget? animatedWidget) {
return SizedBox(
height: context.height,
width: context.width,
child: Stack(
children: [
DrawerBarView(
onTapItem: (index) {
setState(() {
currentIndex = index;
});
},
animationController: _animationController,
isColapsed: isCollapsed,
menuCloseTapped: () {
setState(() {
isCollapsed = !isCollapsed;
isCollapsed
? _animationController.forward()
: _animationController.reverse();
});
},
widthAnimation: widthAnimation,
selectedIndex: currentIndex,
userModel: Get.put(UserProvider()).userData!,
),
Positioned(
left: widthAnimation.value,
child: Container(
decoration: BoxDecoration(
boxShadow: const [
BoxShadow(
color: Colors.black12,
blurRadius: 20,
spreadRadius: 5,
)
],
color: ColorConstants.white,
borderRadius: const BorderRadius.only(
topLeft: Radius.circular(40),
)),
height: context.height,
width: context.width,
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
HeaderView(
userModel: Get.put(UserProvider()).userData!,
),
Expanded(
child: widget.pages[currentIndex])
],
),
),
),
],
),
);
}));
}
}
Also i am using GetX package in my project. Could this cause such a problem?