flutter_citizen_printer #

Flutter plugin for Citizen label printers via USB and WiFi.

Requirements #

• Flutter 3.x
• Android SDK 19+
• Proprietary library CSJLabelLib_Android.jar (provided separately)

Installation #

Add to your pubspec.yaml:

dependencies:
  flutter_citizen_printer: ^0.0.3    

Android Native Library #

1. Download and accept the CSJLabelLib_Android.jar along with its EULA (see EULA_Citizen_Systems_Japan.txt).
2. Copy CSJLabelLib_Android.jar into the android/libs/ folder of your Flutter project.

Usage #

Import the plugin:

import 'package:flutter_citizen_printer/flutter_citizen_printer.dart';

Print via USB (single printer) #

final bytes = (await rootBundle.load('assets/sample.bmp')).buffer.asUint8List();
await FlutterCitizenPrinter.printImageUSB(bytes);

Multiple USB Printers Support (NEW in v0.0.3) #

Search for USB printers

List<UsbPrinterInfo> printers = await FlutterCitizenPrinter.searchUsbPrinters();
print('Found ${printers.length} USB printers');

for (UsbPrinterInfo printer in printers) {
  print('Printer: ${printer.displayName}');
  print('Device ID: ${printer.deviceId}');
  print('Manufacturer: ${printer.manufacturerName}');
  print('Product: ${printer.productName}');
  print('Vendor ID: ${printer.vendorId}');
  print('Product ID: ${printer.productId}');
}

Print to specific USB printer

// Select a specific printer from the list
UsbPrinterInfo selectedPrinter = printers[0]; // or from user selection

// Print to the selected printer
final bytes = (await rootBundle.load('assets/sample.bmp')).buffer.asUint8List();
await FlutterCitizenPrinter.printImageUsbSpecific(
  selectedPrinter.deviceId,
  bytes,
);

Print via WiFi #

final bytes = (await rootBundle.load('assets/sample.bmp')).buffer.asUint8List();
await FlutterCitizenPrinter.printImageWiFi(
  '192.168.0.100', // printer IP
  bytes,
  width, // image width
  height, // image height
);

Discover printers on LAN #

final ips = await FlutterCitizenPrinter.detectPrinters(timeout: 3); // 3 seconds timeout
print('Detected printers: $ips');

Check USB printer status #

final status = await FlutterCitizenPrinter.getUsbStatus();
print('USB Status: ${status.map((e) => e.name).join(", ")}');

API Reference #

Classes #

UsbPrinterInfo

Represents information about a USB printer:

• deviceId: Unique identifier for the printer
• deviceName: System device name
• manufacturerName: Manufacturer name
• productName: Product name
• vendorId: USB vendor ID
• productId: USB product ID
• displayName: User-friendly display name

Methods #

searchUsbPrinters()

Returns a list of all connected USB printers as List<UsbPrinterInfo>.

printImageUsbSpecific(String deviceId, Uint8List imageBytes)

Prints an image to a specific USB printer identified by its device ID.

printImageUSB(Uint8List imageBytes)

Prints an image to the first available USB printer (legacy method).

printImageWiFi(String ip, Uint8List imageBytes, int width, int height)

Prints an image to a WiFi printer at the specified IP address.

detectPrinters({int timeout = 3})

Discovers Citizen printers on the local network via WiFi.

getUsbStatus()

Gets the status of the USB printer connection.

Example #

See the complete example in the /example folder which demonstrates:

• Searching for multiple USB printers
• Selecting a specific printer from a list
• Printing to the selected printer
• WiFi printer discovery and printing

Changelog #

Version 0.0.3 #

• Multiple USB printers support: Added ability to manage and print to multiple USB printers simultaneously
• New searchUsbPrinters() method to find all connected USB printers
• New printImageUsbSpecific() method to print to a specific printer
• Added UsbPrinterInfo class for printer information
• Enhanced example app with printer selection UI

Version 0.0.2 #

• Bug fixes and improvements

Version 0.0.1 #

• Initial release with basic USB and WiFi printing support