Save pdf file in external storage in flutter

Question

I have an option in my app where user can export the pdf document for that I am creating the pdf in app using PDF library and I am viewing the pdf also after creating using flutter_full_pdf_viewer Now I want to save this pdf file in the device using external storage I am not able to achieve this Kindly help

I am able to create and view this pdf but now I want to save this PDF in a path in external storage by creating a directory in external storage.

I am posting the code that I have used Kindly suggest the method.

 goTocreatePdf(context) async {
   final Document pdf = Document();

  pdf.addPage(MultiPage(
  pageFormat:
  PdfPageFormat.letter.copyWith(marginBottom: 1.5 * PdfPageFormat.cm),
  crossAxisAlignment: CrossAxisAlignment.start,
  header: (Context context) {
    if (context.pageNumber == 1) {
      return null;
    }
    return Container(
        alignment: Alignment.centerRight,
        margin: const EdgeInsets.only(bottom: 3.0 * PdfPageFormat.mm),
        padding: const EdgeInsets.only(bottom: 3.0 * PdfPageFormat.mm),
        decoration: const BoxDecoration(
            border:
            BoxBorder(bottom: true, width: 0.5, color: PdfColors.grey)),
        child: Text('Report',
            style: Theme.of(context)
                .defaultTextStyle
                .copyWith(color: PdfColors.grey)));
  },
  footer: (Context context) {
    return Container(
        alignment: Alignment.centerRight,
        margin: const EdgeInsets.only(top: 1.0 * PdfPageFormat.cm),
        child: Text('Page ${context.pageNumber} of ${context.pagesCount}',
            style: Theme.of(context)
                .defaultTextStyle
                .copyWith(color: PdfColors.grey)));
  },
  build: (Context context) => <Widget>[
    Header(
        level: 0,
        child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: <Widget>[
              Text('Report', textScaleFactor: 2),
              PdfLogo()
            ])),
    Header(level: 1, text: 'What is Lorem Ipsum?'),
    Paragraph(
        text:
        'Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.'),
    Paragraph(
        text:
        'It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using "Content here, content here", making it look like readable English. Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for "lorem ipsum" will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like).'),
    Header(level: 1, text: 'Where does it come from?'),
    Paragraph(
        text:
        'Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.'),
    Paragraph(
        text:
        'Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.'),
    Padding(padding: const EdgeInsets.all(10)),
    Table.fromTextArray(context: context, data: const <List<String>>[
      <String>['Year', 'Ipsum', 'Lorem'],
      <String>['2000', 'Ipsum 1.0', 'Lorem 1'],
      <String>['2001', 'Ipsum 1.1', 'Lorem 2'],
      <String>['2002', 'Ipsum 1.2', 'Lorem 3'],
      <String>['2003', 'Ipsum 1.3', 'Lorem 4'],
      <String>['2004', 'Ipsum 1.4', 'Lorem 5'],
      <String>['2004', 'Ipsum 1.5', 'Lorem 6'],
      <String>['2006', 'Ipsum 1.6', 'Lorem 7'],
      <String>['2007', 'Ipsum 1.7', 'Lorem 8'],
      <String>['2008', 'Ipsum 1.7', 'Lorem 9'],
    ]),
  ]));
 //save PDF
  final String dir = (await getApplicationDocumentsDirectory()).path;
  final String path = '$dir/report.pdf';
  Dio dio = new Dio();
  final File file = File(path);
 //  await dio.download(, path);
  await file.writeAsBytes(pdf.save());
  material.Navigator.of(context).push(
  material.MaterialPageRoute(
  builder: (_) => PdfViewerPage(path: path),
  ),
);

}

this is for viewing pdf I created

 class PdfViewerPage extends StatelessWidget {
  final String path;
  const PdfViewerPage({Key key, this.path}) : super(key: key);

 @override
 Widget build(BuildContext context) {
 return PDFViewerScaffold(
  path: path,
  );
  }
 }

Answer 1

To provide the path where the file will be written, you can use the external_path plugin. As for gaining write access to storage, you need to manage the device permissions. For this, you can use permission_handler plugin.

if (await Permission.storage.request().isGranted) {
  // write pdf file
}