问颤振:我需要干净的方式来使用youtube_explode_dart包来保存视频

EN

  Future<void> downloadVideo(id) async {
    var permisson = await Permission.storage.request();
    if (permisson.isGranted) {
      //download video
      if (_urlTextFieldController.text != '') {
        setState(() => _downloading = true);

        //download video
        setState(() => progress = 0);
        var _youtubeExplode = YoutubeExplode();
        //get video metadata
        var video = await _youtubeExplode.videos.get(id);
        var manifest =
            await _youtubeExplode.videos.streamsClient.getManifest(id);
        var streams = manifest.muxed.withHighestBitrate();
        var audio = streams;
        var audioStream = _youtubeExplode.videos.streamsClient.get(audio);
        //create a directory
        Directory appDocDir = await getApplicationDocumentsDirectory();
        String appDocPath = appDocDir.path;
        var file = File('$appDocPath/${video.id}');
        //delete file if exists
        if (file.existsSync()) {
          file.deleteSync();
        }
        var output = file.openWrite(mode: FileMode.writeOnlyAppend);
        var size = audio.size.totalBytes;
        var count = 0;

        await for (final data in audioStream) {
          // Keep track of the current downloaded data.
          count += data.length;
          // Calculate the current progress.
          double val = ((count / size));
          var msg = '${video.title} Downloaded to $appDocPath/${video.id}';
          for (val; val == 1.0; val++) {
            ScaffoldMessenger.of(context)
                .showSnackBar(SnackBar(content: Text(msg)));
          }
          setState(() => progress = val);

          // Write to file.
          output.add(data);
        }
      } else {
        ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(content: Text('add youtube video url first!')));
        setState(() => _downloading = false);
      }
    } else {
      await Permission.storage.request();
    }
  }