如何停止在 flutter 中覆盖同一个文件?

How to stop overwriting on the same file in flutter?

我想单独保存文件。我用过"Files.writeAsBytes(pdf.save())",但问题是,它覆盖了同一个文件。

  savePDFfile(context) async {
    final String dir = (await getExternalStorageDirectory()).path;
    final String path = '$dir/pdf.pdf';
    final file = File(path);
    await file.exists()? file.delete():
    file.writeAsBytes(pdf.save());
    print("file saved");
    mat.Navigator.of(context)
        .push(mat.MaterialPageRoute(builder: (_) => PdfViewerPage(path: path)));
  }

每次保存pdf时都需要更改文件路径。例如,通过向路径添加时间戳 -

final String path = '$dir/pdf${DateTime.now().toIso8601String())}.pdf';