Turn on the animation in initstate and the animation will jump. about flutter HOT 6 CLOSED

import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart';

class BugApp extends StatelessWidget {
  const BugApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(onGenerateRoute: (settings) {
      return MaterialPageRoute(builder: (context) => const Bug());
    });
  }
}

class Bug extends StatefulWidget {
  const Bug({super.key});

  @override
  State<StatefulWidget> createState() => _BugState();
}

class _BugState extends State<Bug> with SingleTickerProviderStateMixin {
  static final tween = Tween(begin: Offset.zero, end: const Offset(1, 0));
  late final AnimationController _controller;
  late final Animation<Offset> _animation;
  Animation<double>? _routeAnimation;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: const Duration(seconds: 2),
      vsync: this,
    );
    _animation = tween.animate(_controller);
  }

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    if (_routeAnimation == null) {
      _routeAnimation =
          ModalRoute.of(context)?.animation ?? kAlwaysCompleteAnimation;
      _routeAnimation!.addStatusListener(_handleAnimationStatusChange);
    }
  }

  @override
  void dispose() {
    _routeAnimation?.removeStatusListener(_handleAnimationStatusChange);
    _routeAnimation = null;
    _controller.dispose();
    super.dispose();
  }

  void _handleAnimationStatusChange(AnimationStatus status) {
    if (status == AnimationStatus.completed) {
      _controller.forward();
    }
  }

  @override
  Widget build(BuildContext context) {
    timeDilation = 10; // This allows you to view the animation in slow motion.
    final size = MediaQuery.sizeOf(context);
    return Scaffold(
      appBar: AppBar(
        title: const Text("animation"),
      ),
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SlideTransition(
            position: _animation,
            child: Container(
              width: size.width / 2,
              height: size.width / 2,
              color: Colors.grey,
            ),
          ),
          TextButton(
            onPressed: () {
              Navigator.of(context).push(
                MaterialPageRoute(builder: (context) => const Bug()),
              );
            },
            child: const Text("Push new page"),
          )
        ],
      ),
    );
  }
}