使用 flutter 打印 package，如何从 ZE6B391A8D2C4D45902A23A8B68Z 打印 PDF？

Question

I am using the printing package in flutter: https://pub.dev/packages/printing

The documentation shows how to create PDFs from scratch. I already have a PDF at a URL. Is there a way to retrieve it and print it with the package? Or is there an alternate method with another package?

Answer 1

I have tried the following ways to achieve the printing feature:

• Directly get the remote data bytes
  With the popular package printing

var data = await http.get(url);
await Printing.layoutPdf(onLayout: (_) => data.bodyBytes);

But I found that this way will have the printing area disorder issue when printing a roller size paper (POS printer)

• Sharing (alternative of the first one)
  Use the sharePdf function

var data = await http.get(url);
await Printing.sharePdf(bytes: data.bodyBytes, filename: 'my-document.pdf');

This one needs an additional step to print (click the 'functions' icon of browser then print)

• View it from the browser and print it natively
  Check out this package url_launcher

import 'package:url_launcher/url_launcher.dart';

if (await canLaunch(url)) {
  await launch(url);
}

This one needs an additional step to print (click the 'functions' icon of browser then print)

• Download the remote file and save it, use the flutter_pdf_printer package.
  Use this package flutter_pdf_printer and path_provider

var data = await http.get(url);
final output = await getTemporaryDirectory();
final file = File('${output.path}/your_file_name_${new DateTime.now().microsecondsSinceEpoch}.pdf');
await file.writeAsBytes(data.bodyBytes);
await FlutterPdfPrinter.printFile(file.path);

*** this package will have channel registrant issue , please run flutter clean after installation ***
This package is a little bit outdated, but it works for me to print with a roller 80 size pdf. It uses the Swift UIKit package, which has good compatibility.

Summary

My scenario is to print a roller 80 size pdf with infinite height, the printing package doesn't work for cuz it cannot preview the pdf properly. So I changed to the last way to print, which works for me. If you just print an A4 or a regular size PDF, the printing package is still a good choice.

Answer 2

From the plugin documentation To save the pdf file using the path_provider library:

    final output = await getTemporaryDirectory();
final file = File("${output.path}/example.pdf");
await file.writeAsBytes(pdf.save());

print the document using the iOS or Android print service

await Printing.layoutPdf(
  onLayout: (PdfPageFormat format) async => pdf.save());

Answer 3

Convert your string url to URI, please make sure you are adding http

http: ^0.13.4

import 'package:http/http.dart' as http;

Uri uri = Uri.parse('Your link here');
                        http.Response response = await http.get(uri);
                        var pdfData = response.bodyBytes;
                        await Printing.layoutPdf(onLayout: (PdfPageFormat 
                        format) async => pdfData);