Flutter:如何从视频中获取图像，

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

class VideoPlayerScreen extends StatefulWidget {
  @override
  _VideoPlayerScreenState createState() => _VideoPlayerScreenState();
}

class _VideoPlayerScreenState extends State<VideoPlayerScreen> {
  VideoPlayerController _controller;
  Image _screenshot;

  @override
  void initState() {
    super.initState();
    _controller = VideoPlayerController.network(
        'https://example.com/video.mp4');
    _controller.initialize().then((_) {
      setState(() {});
    });
  }

  Future<void> _captureScreenshot() async {
    final image = await _controller.videoPlayerController.takeSnapshot();
    setState(() {
      _screenshot = Image.memory(
        image,
        fit: BoxFit.contain,
      );
    });
  }

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

  @override
  Widget build(BuildContext context) {
    if (_controller.value.isInitialized) {
      return Scaffold(
        body: Stack(
          children: [
            Center(
              child: AspectRatio(
                aspectRatio: _controller.value.aspectRatio,
                child: VideoPlayer(_controller),
              ),
            ),
            Positioned(
              bottom: 20,
              right: 20,
              child: FloatingActionButton(
                onPressed: _captureScreenshot,
                child: Icon(Icons.camera),
              ),
            ),
            if (_screenshot != null)
              Positioned(
                top: 20,
                left: 20,
                child: Container(
                  width: 200,
                  height: 200,
                  child: _screenshot,
                ),
              ),
          ],
        ),
      );
    } else {
      return Center(
        child: CircularProgressIndicator(),
      );
    }
  }
}