Run in terminal :

flutter pub run simple_assets_generator:generate -i assets/path/files -o lib -n Images -ext jpeg,png -fn assets_file flutter pub run simple_assets_generator:grouped_generate -i assets/path/files -o lib -n Images -fn assets_file

[required] -i assets directory, in my case assets/path/files

[required] -o generated file output path, lib/assets_names in my case

[optional] -n generated class name

[optional] -fn generated file name

[optional] -ext generate only files with given extensions (not supported for grouped generation)

Open pub.dev

class TxtFiles {
  static String fileTxt = 'assets/path/files/text1.txt';
}

class Images {
  static String logoPng = 'assets/path/files/logo.png';
}

Grouped generation result

abstract class AssetImages {
  static String png1 =
      "assets/path/files/1.png";
  static String png2 =
      "assets/path/files/2.png";
}

abstract class AssetDocuments {
  static String txtText1 =
      "assets/path/files/text1.txt";
  static String txtText2 =
      "assets/path/files/text2.txt";
}