解码器init无法使用Chewie播放Flutter上的视频列表

dependencies:
  chewie: ^x.x.x
  video_player: ^x.x.x

import 'package:flutter/material.dart';
import 'package:chewie/chewie.dart';
import 'package:video_player/video_player.dart';

class VideoPage extends StatefulWidget {
  @override
  _VideoPageState createState() => _VideoPageState();
}

class _VideoPageState extends State<VideoPage> {
  ChewieController _chewieController;

  @override
  void initState() {
    super.initState();
    _chewieController = ChewieController(
      videoPlayerController: VideoPlayerController.network('https://example.com/video.mp4'),
      autoPlay: true,
      looping: true,
    );
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Video Player'),
      ),
      body: Center(
        child: Chewie(
          controller: _chewieController,
        ),
      ),
    );
  }
}