Phidget RFID Reader

A Flutter package for interacting with a Phidget RFID reader on Windows, Linux, and macOS. This package uses FFI to communicate with the native phidget22 library, allowing you to easily integrate Phidget RFID readers into your Flutter applications.

Features

• Cross-Platform: Works on Windows, Linux, and macOS.
• Event-Driven: Provides a stream of events for device attachment, detachment, and tag scanning.
• Simple API: Easy to initialize the device and listen for events.

Prerequisites

You must have the Phidget22 library installed on your system. You can find the installation instructions for your operating system on the Phidgets website.

Installation

Add the following to your pubspec.yaml file:

dependencies:
  phidget_rfid: ^1.0.0

Then, run flutter pub get.

Usage

Here is a simple example of how to use the phidget_rfid package in a Flutter application. This example also shows how to enable logging to see detailed output from the PhidgetRFID class.

First, add the logging package to your pubspec.yaml:

dependencies:
  phidget_rfid: ^1.0.0
  logging: ^1.2.0 # Or the latest version

Then, you can use the following code in your application:

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:phidget_rfid/phidget_rfid.dart';
import 'package:logging/logging.dart';

void main() {
  // Enable logging to see the output from the PhidgetRFID class
  Logger.root.level = Level.ALL;
  Logger.root.onRecord.listen((record) {
    print('${record.level.name}: ${record.time}: ${record.message}');
  });

  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Phidget RFID Reader',
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.teal),
        useMaterial3: true,
      ),
      home: const MyHomePage(title: 'Phidget RFID Reader Demo'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});
  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  late PhidgetRFID _phidgetService;
  StreamSubscription<PhidgetEvent>? _eventSubscription;

  String _status = 'Disconnected';
  String _lastTag = 'N/A';

  @override
  void initState() {
    super.initState();
    _phidgetService = PhidgetRFID();
    _connectPhidget();
  }

  void _connectPhidget() async {
    setState(() {
      _status = 'Initializing...';
      _lastTag = 'N/A';
    });

    try {
      await _phidgetService.initialize();

      _eventSubscription = _phidgetService.eventStream.listen((event) {
        if (!mounted) return;
        setState(() {
          switch (event) {
            case PhidgetAttachedEvent():
              _status = 'Connected';

            case PhidgetDetachedEvent():
              _status = 'Disconnected';
              _lastTag = 'N/A';

            case PhidgetTagScannedEvent():
              _status = 'Connected';
              _lastTag = event.tag;

            // --- THIS CASE IS UPDATED ---
            case PhidgetTagLostEvent():
              // When a tag is lost, revert to the connected state and clear the tag.
              _status = 'Connected';
              _lastTag = 'N/A';

            default:
              _status = 'Unknown Event';
              print(
                'Warning: Unhandled PhidgetEvent of type '{$event.runtimeType}' received.',
              );
          }
        });
      });
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _status = 'Error: ${e.toString()}';
      });
    }
  }

  void _disconnectPhidget() {
    _eventSubscription?.cancel();
    _phidgetService.dispose();

    _phidgetService = PhidgetRFID();

    setState(() {
      _status = 'Disconnected';
      _lastTag = 'N/A';
    });
  }

  @override
  void dispose() {
    _eventSubscription?.cancel();
    _phidgetService.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final bool isConnected = _status == 'Connected';

    return Scaffold(
      appBar: AppBar(
        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'Status: $_status',
              style: Theme.of(context).textTheme.headlineSmall,
            ),
            const SizedBox(height: 20),
            Text(
              'Last Tag Scanned:', // Label is now simplified
              style: Theme.of(context).textTheme.titleLarge,
            ),
            Text(
              _lastTag,
              style: Theme.of(context).textTheme.headlineMedium?.copyWith(
                fontWeight: FontWeight.bold,
                color: Colors.teal,
              ),
            ),
            const SizedBox(height: 40),
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: [
                ElevatedButton(
                  onPressed: isConnected ? null : _connectPhidget,
                  child: const Text('Connect'),
                ),
                ElevatedButton(
                  onPressed:
                      _status != 'Disconnected' ? _disconnectPhidget : null,
                  child: const Text('Disconnect'),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

API

PhidgetRFID

The main class for interacting with the Phidget RFID reader.

PhidgetRFID()

Creates an instance of the PhidgetRFID service and loads the native phidget22 library.

Future<void> initialize()

Initializes the connection to the Phidget RFID reader and starts listening for events. Throws an exception if the device cannot be found or opened.

Stream<PhidgetEvent> get eventStream

A stream of PhidgetEvents from the RFID reader.

void dispose()

Closes the connection to the RFID reader and releases all native resources.

PhidgetEvent

A sealed class for all Phidget events.

• PhidgetAttachedEvent: Fired when the Phidget RFID reader is attached.
• PhidgetDetachedEvent: Fired when the Phidget RFID reader is detached.
• PhidgetTagScannedEvent: Fired when an RFID tag is scanned. Contains the tag string.
• PhidgetTagLostEvent: Fired when a previously scanned RFID tag is lost. Contains the tag string.

License

This project is licensed under the MIT License - see the LICENSE file for details.