Sliding using RepeatingAnimationBuilder

main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(const MaterialApp(home: SlidingSquarePage()));
}

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: RepeatingAnimationBuilder<Offset>(
          animatable: Tween<Offset>(
            begin: const Offset(-1.0, 0.0), 
            end: const Offset(1.0, 0.0),
          ),
          duration: const Duration(seconds: 1),
          repeatMode: RepeatMode.reverse,
          curve: Curves.easeInOut,
          builder: (context, offset, child) {
            return FractionalTranslation(
              translation: offset,
              child: child,
            );
          },
          child: const ColoredBox(
            color: Colors.green,
            child: SizedBox.square(dimension: 100),
          ),
        ),
      ),
    );
  }
}