CheapBarcodes.Scanning 1.1.0

CheapBarcodes.Scanning

RT150 handheld barcode scanner integration for Android, UI-agnostic. Wraps the CN.Pda serial-port SDK (via CheapBarcodes.Binding) plus the vendor broadcast fallback behind two small types:

• IHardwareScannerService / AndroidHardwareScannerService — scan event stream with beep + vibration feedback (NullHardwareScannerService for non-Android targets).
• Rt150ScannerHost — activity-lifecycle host for the scan thread and receivers.
• KeyboardWedgeDetector — platform-neutral detector for USB/Bluetooth HID scanners that type like keyboards (fast burst + Enter). Works on any platform, including desktop workstations.

Usage

Register the service (MAUI shown; any Android DI works):

#if ANDROID
builder.Services.AddSingleton<IHardwareScannerService, AndroidHardwareScannerService>();
#else
builder.Services.AddSingleton<IHardwareScannerService, NullHardwareScannerService>();
#endif

Wire the host into your MainActivity:

private Rt150ScannerHost _scannerHost;

protected override void OnCreate(Bundle savedInstanceState)
{
    base.OnCreate(savedInstanceState);
    _scannerHost = new Rt150ScannerHost(this);
    _scannerHost.BarcodeScanned += barcode =>
    {
        var scannerService = /* resolve IHardwareScannerService */;
        scannerService?.OnScan(barcode);
    };
}

protected override void OnStart() { base.OnStart(); _scannerHost.Start(); }
protected override void OnResume() { base.OnResume(); _scannerHost.Start(); }
protected override void OnPause() { UnhookIfNeeded(); _scannerHost.Stop(); base.OnPause(); }
protected override void OnDestroy() { _scannerHost.Dispose(); base.OnDestroy(); }

Then consume scans anywhere via IHardwareScannerService.HardwareBarcodeScanned.

Keyboard-wedge (HID) scanners

Most budget USB and Bluetooth scanners present as keyboards. Register a KeyboardWedgeDetector, route its scans into the same pipeline, and feed it key events:

builder.Services.AddSingleton(sp =>
{
    var detector = new KeyboardWedgeDetector();   // MaxInterKeyGap / MinBarcodeLength are tunable
    detector.BarcodeScanned += code => sp.GetService<IHardwareScannerService>()?.OnScan(code);
    return detector;
});

On Android, observe keys at activity level (works regardless of UI focus):

public override bool DispatchKeyEvent(KeyEvent e)
{
    _detector?.ProcessKeyEvent(e);   // extension method, never consumes the event
    return base.DispatchKeyEvent(e);
}

On other platforms, feed ProcessCharacter(char) / ProcessTerminator() from whatever key source the UI has (e.g. a focused input's keydown events). Human typing is filtered out by burst timing.

The RT150's native libraries (libdevapi.so, libirdaSerialPort.so, armeabi-v7a) and scan.jar ship via the CheapBarcodes.Binding dependency — no manual jniLibs setup needed.

See the CheapBarcodes demo app for a working MAUI Blazor frontend.