How to print a List of Widgets to PDF

Question

How can I print this list of widgets using the printing package?

I get an Unhandled Exception: type List<Widget> is not a subtype of type List<Widget> in type cast

The error I keep getting is that the packages do not match. I even tried casting the getBarcodes() as List<pw.Widget> to see if it would work.

In the end, what I want is a sheet of barcodes that I can print out. I think the problem is the SinglechildScrollview but I'm not certain of that.

class _BarcodeScreenState extends State<BarcodeScreen> {
final doc = pw.Document();

List<Widget> getBarcodes() {
 List<Widget> barcodeList = List.generate(
     3,
         (index) => SingleChildScrollView(
         scrollDirection: Axis.horizontal,
         child: Row(
           children: List.generate(
             3,
                 (index) => Padding(
               padding: const EdgeInsets.all(8.0),
               child: Column(
                 children: [
                   Container(
                     decoration: BoxDecoration(
                         border: Border.all(color: Colors.black)),
                     child: Padding(
                       padding: const EdgeInsets.all(8.0),
                       child: BarcodeWidget(
                         data:
                         '${DateFormat('MM d y').format(DateTime.now())} ${nanoid(5)}',
                         barcode: Barcode.code128(),
                       ),
                     ),
                   ),
                 ],
               ),
             ),
           ),
         )));

 return barcodeList;
}

Above is my list of widgets and below is the code I use to try and print it.

  @override
  Widget build(BuildContext context) {
   return SteriCodeBoiler(
      appBarTitle: "Barcodes",
      print: IconButton(
        icon: Icon(Icons.print),
        onPressed:() async{
          doc.addPage(pw.Page(
              pageFormat: PdfPageFormat.a4,
              build: (pw.Context context) {
                return pw.Container(
                    child: pw.ListView(
                        children: getBarcodes()
                    )
                ); 
              }));
          await Printing.layoutPdf(
              onLayout: (PdfPageFormat format) async => doc.save());

        },
      ),
      screenContent: Container(
          child: ListView(
            children:  getBarcodes(),
          )),
    );
  }

}