pos_printer_unity #

A unified Flutter plugin for POS terminal thermal printers. One API, multiple terminal brands, zero headaches.

Features #

• Unified API — Single PosPrinterUnity class for all terminal printers
• Auto-detection — Automatically detects the terminal brand via device model
• Text printing — Print formatted text directly
• Bitmap printing — Print images (PNG/JPEG) as bitmaps
• Paper feed — Control paper feeding
• Status check — Query printer status (ready, out of paper, etc.)
• Extensible — Easy adapter pattern to add new terminal brands

🖨️ Supported Terminals #

Getting Started #

Installation #

dependencies:
  pos_printer_unity: ^0.0.1

Then run:

flutter pub get

Basic Usage #

import 'package:pos_printer_unity/pos_printer_unity.dart';

final printer = PosPrinterUnity();

// Initialize (auto-detects terminal brand)
final initResult = await printer.init();
if (!initResult.success) {
  print('Error: ${initResult.errorMessage}');
  return;
}

// Print text
final result = await printer.printText('Hello from POS Printer Unity!');
print('Print ${result.success ? "OK" : "FAILED"}');

// Print a bitmap image
final bytes = await rootBundle.load('assets/receipt.png');
final bitmapResult = await printer.printBitmap(bytes.buffer.asUint8List());

// Feed paper
await printer.feedPaper(lines: 5);

// Check status
final status = await printer.getStatus();
print('Printer status: ${status.name}');

Specify a Brand #

// Force Positivo printer
final result = await printer.init(brand: PrinterBrand.positivo);

API Reference #

PosPrinterUnity #

PrinterBrand #

enum PrinterBrand { positivo, pax, gertec, posmp, ingenico, auto }

PrinterStatus #

enum PrinterStatus { ready, printing, error, outOfPaper, notInitialized, unknown }

PrintResult #

class PrintResult {
  final bool success;
  final String? errorMessage;
  final int? errorCode;
}

Platform Support #

This plugin is designed exclusively for Android POS terminals with built-in thermal printers.

Adding a New Terminal Brand #

1. Create an adapter implementing IPrinterAdapter:

public class MyBrandAdapter implements IPrinterAdapter {
    @Override public void init(PrinterAdapterCallback callback) { /* ... */ }
    @Override public void printBitmap(Bitmap bitmap, PrinterAdapterCallback callback) { /* ... */ }
    @Override public void printText(String text, PrinterAdapterCallback callback) { /* ... */ }
    @Override public void feedPaper(int lines) { /* ... */ }
    @Override public String getStatus() { /* ... */ }
    @Override public String getBrand() { return "MY_BRAND"; }
}

2. Add the vendor SDK (.aar) to the local Maven repo under android/repo/
3. Register model detection in PrinterFactory.java
4. Add the brand to PrinterBrand enum in Dart

License #

MIT License — see LICENSE for details.