解释有关在flutter中移动文本的一些代码

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Moving Text Example'),
        ),
        body: Center(
          child: AnimatedText(),
        ),
      ),
    );
  }
}

class AnimatedText extends StatefulWidget {
  @override
  _AnimatedTextState createState() => _AnimatedTextState();
}

class _AnimatedTextState extends State<AnimatedText>
    with SingleTickerProviderStateMixin {
  AnimationController _controller;
  Animation<Offset> _animation;

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

    _animation = Tween<Offset>(
      begin: Offset(-1.0, 0.0),
      end: Offset(1.0, 0.0),
    ).animate(_controller);

    _controller.repeat(reverse: true);
  }

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

  @override
  Widget build(BuildContext context) {
    return SlideTransition(
      position: _animation,
      child: Text(
        'Moving Text',
        style: TextStyle(fontSize: 24),
      ),
    );
  }
}