sunmi_external_cloud_printer 0.1.0

Flutter plugin for Sunmi external cloud printers (NT21x/NT31x/NT32x) via USB, LAN, and Bluetooth. Android only.

sunmi_external_cloud_printer

A Flutter plugin for Sunmi external cloud printers — NT21x, NT31x, and NT32x series — over USB, LAN, and Bluetooth. Android only.

Features

• Scan for nearby Sunmi cloud printers (USB, LAN, Bluetooth)
• Connect and disconnect by printer ID
• Query printer status (isReady, description)
• Build and commit rich print jobs with a fluent PrintJob API:
  • Text alignment (left / center / right)
  • Character size multiplier (width × height, 1–4)
  • Bold text
  • Line feeds
  • Full or partial paper cut
  • QR code printing (size 1–16, four error-correction levels)

Getting started

Prerequisites

• Android only (iOS is not supported by Sunmi hardware)
• Flutter >=3.3.0, Dart SDK >=3.8.1
• A physical Sunmi NT21x, NT31x, or NT32x device

Add the dependency

dependencies:
  sunmi_external_cloud_printer: ^0.1.0

Then run:

flutter pub get

No additional Android permissions are required beyond those already declared by the plugin.

Usage

1 — Scan for printers

import 'package:sunmi_external_cloud_printer/sunmi_external_cloud_printer.dart';

final printer = SunmiExternalCloudPrinter();

final printers = await printer.scan(timeoutSeconds: 5);
for (final p in printers) {
  print('${p.name} [${p.connectionType}] — ${p.id}');
}

2 — Connect

final connected = await printer.connect(printers.first.id);
if (!connected) {
  print('Connection failed');
  return;
}

3 — Build and commit a print job

final result = await printer.commit(
  PrintJob()
    ..initStyle()
    ..setAlignment(PrintAlignment.center)
    ..setCharacterSize(2, 2)
    ..appendText('RECEIPT\n')
    ..setCharacterSize(1, 1)
    ..setAlignment(PrintAlignment.left)
    ..appendText('Item 1 ............... 10.00\n')
    ..appendText('Item 2 ............... 25.00\n')
    ..setBold(enabled: true)
    ..appendText('Total ................ 35.00\n')
    ..setBold(enabled: false)
    ..printQrCode('https://example.com/order/123', size: 6)
    ..lineFeed(3)
    ..cutPaper(),
);

if (result.success) {
  print('Printed: ${result.message}');
} else {
  print('Error: ${result.message}');
}

4 — Check status and disconnect

final status = await printer.getStatus();
print('Ready: ${status.isReady} — ${status.description}');

await printer.disconnect();

A full working example is available in the /example folder.

API reference

SunmiExternalCloudPrinter

Method	Returns	Description
scan({int timeoutSeconds})	Future<List<DiscoveredPrinter>>	Scans for nearby printers
connect(String id)	Future<bool>	Connects to a printer by ID
isConnected()	Future<bool>	Whether a printer is currently connected
disconnect()	Future<void>	Disconnects and releases the connection
getStatus()	Future<PrinterStatus>	Returns current printer status
commit(PrintJob job)	Future<PrintResult>	Executes all job commands and flushes to printer

PrintJob commands

Method	Description
initStyle()	Resets all style settings to defaults
setAlignment(PrintAlignment)	left, center, or right
setCharacterSize(int w, int h)	Width and height multiplier 1–4
setBold({required bool enabled})	Bold on/off
appendText(String text)	Appends text; use \n for line breaks
lineFeed([int lines])	Feeds blank lines (default 1)
cutPaper({bool partial})	Full cut (default) or partial cut
printQrCode(String data, {int size, QrErrorLevel errorLevel})	Prints a QR code

Additional information

• Issues: github.com/YaserH25/sunmi_external_cloud_printer/issues
• Repository: github.com/YaserH25/sunmi_external_cloud_printer
• Contributions are welcome — please open an issue before submitting a large PR.
• Responses to issues are provided on a best-effort basis.