How to render Uint8List as a pdf?

Question

I currently have this function that returns a Uint8List. I would like to render it as a pdf in my android app so I can see it. Not sure how to do this, any help is appreciated! This is the source code if that is also of any help. Thank you https://github.com/DavBfr/dart_pdf/blob/master/demo/lib/invoice.dart

 Future<Uint8List> generateInvoice(PdfPageFormat pageFormat) async {
  final lorem = pw.LoremText();

  final products = <Product>[
    Product('19874', lorem.sentence(4), 3.99, 2),
    Product('98452', lorem.sentence(6), 15, 2),
    Product('28375', lorem.sentence(4), 6.95, 3),
    Product('95673', lorem.sentence(3), 49.99, 4),
    Product('23763', lorem.sentence(2), 560.03, 1),
    Product('55209', lorem.sentence(5), 26, 1),
    Product('09853', lorem.sentence(5), 26, 1),
   
  ];

  final invoice = Invoice(
    invoiceNumber: '982347',
    products: products,
    customerName: 'Abraham Swearegin',
    customerAddress: '54 rue de Rivoli\n75001 Paris, France',
    paymentInfo:
        '4509 Wiseman Street\nKnoxville, Tennessee(TN), 37929\n865-372-0425',
    tax: .15,
    baseColor: PdfColors.teal,
    accentColor: PdfColors.blueGrey900,
  );

  return await invoice.buildPdf(pageFormat);
}

class Invoice {
  Invoice({
    this.products,
    this.customerName,
    this.customerAddress,
    this.invoiceNumber,
    this.tax,
    this.paymentInfo,
    this.baseColor,
    this.accentColor,
  });

  final List<Product> products;
  final String customerName;
  final String customerAddress;
  final String invoiceNumber;


  static const _darkColor = PdfColors.blueGrey800;
  static const _lightColor = PdfColors.white;

  PdfColor get _baseTextColor =>
      baseColor.luminance < 0.5 ? _lightColor : _darkColor;

  PdfColor get _accentTextColor =>
      baseColor.luminance < 0.5 ? _lightColor : _darkColor;

  double get _total =>
      products.map<double>((p) => p.total).reduce((a, b) => a + b);

  double get _grandTotal => _total * (1 + tax);

  PdfImage _logo;

  Future<Uint8List> buildPdf(PdfPageFormat pageFormat) async {
    // Create a PDF document.
    final doc = pw.Document();

    final font1 = await rootBundle.load('assets/roboto1.ttf');
    final font2 = await rootBundle.load('assets/roboto2.ttf');
    final font3 = await rootBundle.load('assets/roboto3.ttf');

    _logo = PdfImage.file(
      doc.document,
      bytes: (await rootBundle.load('assets/logo.png')).buffer.asUint8List(),
    );

    // Add page to the PDF
    doc.addPage(
      pw.MultiPage(
        pageTheme: _buildTheme(
          pageFormat,
          font1 != null ? pw.Font.ttf(font1) : null,
          font2 != null ? pw.Font.ttf(font2) : null,
          font3 != null ? pw.Font.ttf(font3) : null,
        ),
        header: _buildHeader,
        footer: _buildFooter,
        build: (context) => [
          _contentHeader(context),
          _contentTable(context),
          pw.SizedBox(height: 20),
          _contentFooter(context),
          pw.SizedBox(height: 20),
          _termsAndConditions(context),
        ],
      ),
    );

    // Return the PDF file content
    return doc.save();
  }

Solution

You can save the file locally and render it using some pdf viewer

final String dir = (await getApplicationDocumentsDirectory()).path;
final String path = '$dir/example.pdf';
final File file = File(path);
await file.writeAsBytes(doc.save());

Now you can use this path to view the pdf using a pdf viewer.

You can check this medium post for reference.

Comments

[sj_959]

Thanks. Although this does generate a pdf file, when I try to open the file, I get an error saying Failed to load PDF document.