No implementation found for method file on channel video_thumbnail

在一个flutter项目中，使用了VideoThumbnail来生成视频的截图，但运行会提示“No implementation found for method file on channel video_thumbnail”，相当代码如下：

final thumbnailPath = await VideoThumbnail.thumbnailFile(
    video: video.url,
    thumbnailPath: (await getTemporaryDirectory()).path,
    imageFormat: ImageFormat.WEBP,
    maxHeight: height,
    maxWidth: width,
    // specify the height of the thumbnail, let the width auto-scaled to keep the source aspect ratio
    quality: 75,
  );

查看video.url，可以在浏览器中打开。发现是http开头的，估计是android9.x（api27及以上）默认不允许http请求。使用API23的模拟器确实可以正常跑，于是打开android\app\src\main\AndroidManifest.xml,在其application添加

android:usesCleartextTraffic="true"

No implementation found for method file on channel video_thumbnail

问题解决。以下是我使用的环境

Android Studio 4.1.2

Flutter 2.0.1