关于打印：Flutter在打印机中创建汉字PDF文件并打印文件

Flutter create Chinese character PDF file and print file in printer

我正在尝试开发一个Flutter应用程序，该应用程序可以将文档打印到纸上。我只能使用英文字符。有人可以帮助使其与中文一起使用吗？

这是我的main.dart

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import 'dart:convert';
import 'dart:io';
import 'dart:typed_data';
import 'dart:ui';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:pdf/pdf.dart';
import 'package:printing/printing.dart';

void main() => runApp(new MaterialApp(home: new MyApp()));

class MyApp extends StatelessWidget {
final shareWidget = new GlobalKey();

Future<PDFDocument> _generateDocument() async{
final pdf = new PDFDocument(deflate: zlib.encode);
final page = new PDFPage(pdf, pageFormat: PDFPageFormat(216.0, 384.0));
final g = page.getGraphics();
final top = page.pageFormat.height;

g.setColor(new PDFColor(0.0, 1.0, 1.0));

var font = await rootBundle.load("assets/GenYoMinTW-Heavy.ttf");
PDFTTFFont ttf = new PDFTTFFont(pdf, font);

//PDFTTFFont ttf = new PDFTTFFont(pdf, (new File("assets/open-sans.ttf").readAsBytesSync() as Uint8List).buffer.asByteData());
g.setColor(new PDFColor(0.3, 0.3, 0.3));

//var encoded = utf8.encode("檯號： 1");
g.drawString(ttf, 20.0, '\\u4f60\\u597d', 10.0 * PDFPageFormat.MM, top - 10.0 * PDFPageFormat.MM);

return pdf;
}

void _printPdf() {
print("Print ...");
// final pdf = _generateDocument();
// Printing.printPdf(document: pdf);

_generateDocument().then((pdf) {
Printing.printPdf(document: pdf);
});

}

void _sharePdf() {
print("Share ...");
//final pdf = _generateDocument();

// Calculate the widget center for iPad sharing popup position
final RenderBox referenceBox =
shareWidget.currentContext.findRenderObject();
final topLeft =
referenceBox.localToGlobal(referenceBox.paintBounds.topLeft);
final bottomRight =
referenceBox.localToGlobal(referenceBox.paintBounds.bottomRight);
final bounds = new Rect.fromPoints(topLeft, bottomRight);

_generateDocument().then((pdf) {
Printing.sharePdf(document: pdf, bounds: bounds);
});

}

@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: const Text('Printing example'),
),
body: new Center(
child: new Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
new RaisedButton(
child: new Text('Print Document'), onPressed: _printPdf),
new RaisedButton(
key: shareWidget,
child: new Text('Share Document'),
onPressed: _sharePdf),
],
),
),
);
}
}

使用中文Unicode打印时，屏幕不会进入打印预览页面。

如果有帮助，这是我的pubspec.yaml：

name: testmanual
description: A new Flutter application.

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# Read more about versioning at semver.org.
version: 1.0.0+1

environment:
sdk:">=2.0.0-dev.68.0 <3.0.0"

dependencies:
flutter:
sdk: flutter

# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^0.1.2
image_picker: ^0.4.10
flutter_mailer: ^0.1.1
video_player: ^0.6.5
datetime_picker_formfield: ^0.1.3
device_calendar: ^0.0.6
connectivity: ^0.3.1
path_provider:"^0.4.0"
flutter_date_picker: ^0.1.2
image_form_field: ^0.0.2
flutter_youtube:"^1.1.1"
cached_network_image: ^0.4.2
qr_flutter: ^1.1.3
share: ^0.5.3
audioplayers: ^0.7.8
chewie: ^0.7.0
printing: ^1.0.5
pdf: ^1.0.6
font_awesome_flutter: ^8.1.0

dev_dependencies:
flutter_test:
sdk: flutter

# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true

# To add assets to your application, add an assets section, like this:
assets:
- assets/ding.wav
- assets/qpon_download.pdf
- assets/open-sans.ttf
- assets/GenYoMinTW-Heavy.ttf

# An image asset can refer to one or more resolution-specific"variants", see
# https://flutter.io/assets-and-images/#resolution-aware.

# For details regarding adding assets from package dependencies, see
# https://flutter.io/assets-and-images/#from-packages

# To add custom fonts to your application, add a fonts section here,
# in this"flutter" section. Each entry in this list should have a
#"family" key with the font family name, and a"fonts" key with a
# list giving the asset and other descriptors for the font. For
# example:
# fonts:
# - family: Schyler
# fonts:
# - asset: fonts/Schyler-Regular.ttf
# - asset: fonts/Schyler-Italic.ttf
# style: italic
# - family: Trajan Pro
# fonts:
# - asset: fonts/TrajanPro.ttf
# - asset: fonts/TrajanPro_Bold.ttf
# weight: 700
#
# For details regarding fonts from package dependencies,
# see https://flutter.io/custom-fonts/#from-packages

enter image description here

相关讨论

我之前还没有处理过PDF和Flutter。另外，我目前正在电话中，因此无法检查。我的猜测是编译器不懂汉字吗？如果是这种情况，请尝试直接输入Unicode字符。如果您无法尽快找到解决方法，请在使用计算机时为您提供帮助。
非常感谢你！是的，如果我使用unicode字符进行打印，则可以使用。但是我要打印很多字符，因此我必须将其转换为unicode并进行打印。我想我做错了。因此，它仅打印数字而不是中文。我将更新代码，您将看到。仅供参考，我还在dart_pdf的GITHUB中发布了问题。 github.com/DavBfr/dart_pdf/issues/17
没问题。乐意效劳！我将在此处添加一个答案，以便您可以接受并投票。现在，您可以使用：chineseconverter.com/en/convert/unicode
另外，如果用户在应用程序中输入汉字，则不必手动转换它，因为应用程序已经可以执行此操作。如果将其硬编码到应用程序中，则只需要转换为unicode。
感谢您给我一个将汉字转换为unicode的工具。我想我之前犯了一个错误，它只能打印unicode的符号，不能打印汉字的unicode。
错误消息：[VERBOSE-2：shell.cc(181)] Dart错误：未处理的异常：无效的参数：字符串包含无效字符。＃0 _UnicodeSubsetEncoder.convert(dart：convert / ascii.dart：95：9)＃1 Latin1Codec.encode(dart：convert / latin1.dart：44：46)＃2 PDFStream.putText(file：/// Users / chongto /development/flutter/.pub-cache/hosted /pub.dartlang.org/p f-1.0.6 / lib / src / stre am.dart：79：21)
不便之处，敬请原谅！
我将在今天晚些时候看到我能做什么。您是否看到使用Unicode字符串会发生什么？
我现在将更新代码，然后您可以看到它。
main.dart的第45行是什么？
第45行是_generateDocument()。then((pdf){Printing.printPdf(document：pdf);});
实际上，我不必使用pdf进行打印。但是我只发现这种方法可以打印到打印机。如果还有其他易于打印的汉字方法，请事先告知。我。谢谢
让我们继续聊天中的讨论。
我已经能够使用PDF共享功能，但是我认为我们无法解决该问题。我认为这是PDF库中的问题。
好的，非常感谢您的努力！您知道将文件打印到打印机的任何其他方法吗？我可以使用txt文件进行打印吗？

不幸的是，PDF库似乎只能使用ASCII字符。在这里，我已附加了代码以英语生成PFD。它还可以访问移动设备的"共享"页面，因此您可以将PDF保存到另一个应用程序，或通过AirPrint之类的方法将其发送到打印机。希望这可以帮助。我也重新编写了代码。我将尽快向您的回购请求。您可能想向[PDF] [1]库的作者David PHAM-VAN提交错误报告。

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import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter_share/flutter_share.dart';
import 'package:pdf/pdf.dart';
import 'package:path_provider/path_provider.dart';

void main() => runApp(new MaterialApp(home: new MyApp()));

class MyApp extends StatelessWidget {
Future<PDFDocument> _generateDocument() async{
final pdf = new PDFDocument();
final page = new PDFPage(pdf, pageFormat: PDFPageFormat(216.0, 384.0));
final top = page.pageFormat.height;

final g = page.getGraphics();
final font = new PDFFont(pdf);

g.setColor(new PDFColor(0.3, 0.3, 0.3));
String text ="We can only use ASCII characters";
g.drawString(font, 12.0, text, 1.0 * PDFPageFormat.mm, top-10*PDFPageFormat.mm);

await _localFile.then((File file){
print("Saving local file");
file.writeAsBytesSync(pdf.save());
});
return pdf;
}

void _sharePDF() {
print("Print ...");
_generateDocument().then((pdf) {
_localPath.then((String path){
FlutterShare.share(fileUrl:"$path/pdf.pdf");
});
});

}

Future<File> get _localFile async {
final path = await _localPath;
return File('$path/pdf.pdf');
}

Future<String> get _localPath async {
final directory = await getApplicationDocumentsDirectory();
return directory.path;
}

@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: const Text('Printing example'),
),
body: new Center(
child: new Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: <Widget>[
new RaisedButton(
child: new Text('Print Document'), onPressed: _sharePDF)
],
),
),
);
}
}

编辑：我不知道如何快速发送拉取请求，所以只用此代码替换main.dart即可。这也是您想要的pubspec.yaml代码/

name: testmanual
description: A new Flutter application.

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# Read more about versioning at semver.org.
version: 1.0.0+1

environment:
sdk:">=2.0.0-dev.68.0 <3.0.0"

dependencies:
flutter:
sdk: flutter

# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^0.1.2
image_picker: ^0.4.10
path_provider:"^0.4.0"
qr_flutter: ^1.1.3
printing: ^1.0.5
pdf: ^1.0.6
flutter_share: ^0.0.4
# flutter_mailer: ^0.1.1
# video_player: ^0.6.5
# datetime_picker_formfield: ^0.1.3
# device_calendar: ^0.0.6
# connectivity: ^0.3.1
# flutter_date_picker: ^0.1.2
# image_form_field: ^0.0.2
# flutter_youtube:"^1.1.1"
# cached_network_image: ^0.4.2
# share: ^0.5.3
# audioplayers: ^0.7.8
# chewie: ^0.7.0
# font_awesome_flutter: ^8.1.0

dev_dependencies:
flutter_test:
sdk: flutter

# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

# The following line ensures that the Material Icons font is
# included with your application, so that you can use the icons in
# the material Icons class.
uses-material-design: true

# To add assets to your application, add an assets section, like this:
assets:
- assets/ding.wav
- assets/qpon_download.pdf
- assets/open-sans.ttf
- assets/GenYoMinTW-Heavy.ttf

# An image asset can refer to one or more resolution-specific"variants", see
# https://flutter.io/assets-and-images/#resolution-aware.

# For details regarding adding assets from package dependencies, see
# https://flutter.io/assets-and-images/#from-packages

# To add custom fonts to your application, add a fonts section here,
# in this"flutter" section. Each entry in this list should have a
#"family" key with the font family name, and a"fonts" key with a
# list giving the asset and other descriptors for the font. For
# example:
# fonts:
# - family: Schyler
# fonts:
# - asset: fonts/Schyler-Regular.ttf
# - asset: fonts/Schyler-Italic.ttf
# style: italic
# - family: Trajan Pro
# fonts:
# - asset: fonts/TrajanPro.ttf
# - asset: fonts/TrajanPro_Bold.ttf
# weight: 700
#
# For details regarding fonts from package dependencies,
# see https://flutter.io/custom-fonts/#from-packages

编辑2：

重要！当您将PDF写入文件时，这会将其直接写入手机。例如，如果您使用的是iOS，请转到Files应用，然后您会在其中看到一个名为的文件夹，其中会有" pdf.pdf"。您可能需要进行一些清理或找到其他共享方法。

1	[1]: https://pub.dartlang.org/packages/pdf