part of '../widgets.dart'; typedef PDFViewerState = GlobalKey; abstract class Viewer extends StatelessComponent { const Viewer({super.key, required this.src}); final String src; @override Widget build(BuildContext context) { return buildViewer(context); } Widget buildViewer(BuildContext context); } class FREViewerPDF extends Viewer { const FREViewerPDF({required Key key, required this.url}) : super(key: key as PDFViewerState, src: url); final String url; @override Widget buildViewer(BuildContext context) { return SfPdfViewer.network(src, key: key as PDFViewerState); } }