main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  static const data = ['One', 'Two', 'Three', 'Four', 'Five', 'Six'];

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home:  Scaffold(
        body: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: List.generate(data.length, (i) {
            return FlyingButton(data[i], i * 200);
          }),
        ),
      ),
    );
  }
}

class FlyingButton extends StatefulWidget {
  final String text;
  final int delay;

  FlyingButton(this.text, this.delay);

  @override
  _FlyingButtonState createState() => _FlyingButtonState();
}

class _FlyingButtonState extends State<FlyingButton>
    with SingleTickerProviderStateMixin {
  AnimationController _controller;
  Animation<Offset> _offsetAnimation;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: Duration(milliseconds: 400 + widget.delay),
      vsync: this,
    )..forward();

    _offsetAnimation = Tween<Offset>(
      begin: const Offset(-1, 0.0),
      end: Offset.zero,
    ).animate(CurvedAnimation(
      parent: _controller,
      curve: Curves.easeOut,
    ));
  }

  @override
  Widget build(BuildContext context) {
    return SlideTransition(
      position: _offsetAnimation,
      child: Padding(
        padding: const EdgeInsets.symmetric(
          horizontal: 16,
          vertical: 8,
        ),
        child: RaisedButton(
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(10),
          ),
          child: Text(widget.text),
          onPressed: () {},
        ),
      ),
    );
  }
}