FadeTransition()小部件在flutter中只有一次动画吗？

import 'package:flutter/material.dart';

class MyFadeTransition extends StatefulWidget {
  @override
  _MyFadeTransitionState createState() => _MyFadeTransitionState();
}

class _MyFadeTransitionState extends State<MyFadeTransition>
    with SingleTickerProviderStateMixin {
  AnimationController _controller;
  Animation<double> _animation;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: const Duration(seconds: 1),
      vsync: this,
    );
    _animation = Tween<double>(begin: 0.0, end: 1.0).animate(_controller);
    _controller.forward();
  }

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

  @override
  Widget build(BuildContext context) {
    return FadeTransition(
      opacity: _animation,
      child: Container(
        width: 200,
        height: 200,
        color: Colors.blue,
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: Scaffold(
      appBar: AppBar(
        title: Text('Fade Transition Example'),
      ),
      body: Center(
        child: MyFadeTransition(),
      ),
    ),
  ));
}