gistfile1.txt

import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      home: BouncyBallClone(),
    ),
  );
}

class BouncyBallClone extends StatefulWidget {
  @override
  State<BouncyBallClone> createState() => BouncyBallCloneState();
}

class BouncyBallCloneState extends State<BouncyBallClone> with SingleTickerProviderStateMixin{
  AnimationController controller;
  Animation animation;
  
  @override
  void initState(){
    super.initState();
    controller = AnimationController(duration: Duration(seconds: 1), vsync: this);
    controller.repeat(reverse: true);
    animation = CurvedAnimation(parent: controller, curve: Curves.decelerate);
    controller.forward().whenComplete(()=>controller.repeat(reverse: true),);
    animation.addListener(()=>setState((){}));
  }
  
 
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Center(
            child: Transform.translate(
              offset: Offset(0, animation.value * -200),
              child: CircleAvatar(
                backgroundColor: Colors.blue,
                radius: 50,
              ),
            ),
          ),
          Transform.scale(
            scale: 1 - animation.value,
            child: Container(
              width: 100,
              height: 20,
              color: Colors.black
            ),
          ),
        ],
      ),
    
    );
  }
}