Anim Example with Tween

main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.light().copyWith(
        scaffoldBackgroundColor: Colors.white,
      ),
      debugShowCheckedModeBanner: false,
      home: const RateScreen(),
    );
  }
}

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

  @override
  State<RateScreen> createState() => _RateScreenState();
}

class _RateScreenState extends State<RateScreen> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: [
          Positioned(
            top: 250,
            left: 0,
            right: 0,
            bottom: 0,
            child: Container(
              decoration: const BoxDecoration(
                borderRadius: BorderRadius.only(
                  topLeft: Radius.circular(16),
                  topRight: Radius.circular(16),
                ),
                color: Colors.black87,
              ),
              padding: const EdgeInsets.symmetric(horizontal: 16),
              child: Column(
                mainAxisSize: MainAxisSize.max,
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  SizedBox(
                    height: 100,
                    child: Container(
                      decoration: BoxDecoration(
                        borderRadius: BorderRadius.circular(16),
                        color: Colors.white54,
                      ),
                    ),
                  ),
                  const SizedBox(height: 10),
                  SizedBox(
                    height: 25,
                    child: Container(
                      decoration: BoxDecoration(
                        borderRadius: BorderRadius.circular(16),
                        color: Colors.white54,
                      ),
                    ),
                  ),
                  const SizedBox(height: 50),
                  const _AnimatedButton(),
                  const SizedBox(height: 24),
                ],
              ),
            ),
          )
        ],
      ),
    );
  }
}

class _AnimatedButton extends StatefulWidget {
  const _AnimatedButton();

  @override
  State<_AnimatedButton> createState() => _AnimatedButtonState();
}

class _AnimatedButtonState extends State<_AnimatedButton>
    with SingleTickerProviderStateMixin<_AnimatedButton> {
  late final _controller = AnimationController(
    vsync: this,
    duration: Durations.medium4,
    value: 0,
  )..repeat(reverse: true);

  late final _offset = Tween<Offset>(
    begin: const Offset(-5, 0),
    end: const Offset(5, 0),
  ).animate(
    _controller,
  );

  @override
  void initState() {
    super.initState();

    _controller.addListener(_update);
  }

  @override
  Widget build(BuildContext context) {
    return Transform.translate(
      offset: _offset.value,
      child: ElevatedButton(
        style: ElevatedButton.styleFrom(
          backgroundColor: Colors.amber,
        ),
        onPressed: () {},
        child: const Text('Оценить заказ'),
      ),
    );
  }

  @override
  void dispose() {
    _controller.removeListener(_update);
    _controller.dispose();
    super.dispose();
  }

  void _update() {
    setState(() {});
  }
}