CheapBarcodes.Scanning 2.2.0

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 — ScanReceived event stream of ScanResult (barcode + transport + timestamp) with beep + vibration feedback (NullHardwareScannerService for non-Android targets).
• Rt150ScannerHost — activity-lifecycle host for the RT150 scan thread and receivers.
• IntentScannerHost — generic broadcast-intent host for DataWedge/Honeywell-style devices: configure the action and extra key, get the same ScanResult stream.
• KeyboardWedgeDetector — platform-neutral detector for USB/Bluetooth HID scanners that type like keyboards (fast burst + Enter). Works on any platform, including desktop workstations.
• Gs1Parser / Gtin — pure string logic (no Android needed): GS1-128/DataMatrix element strings decomposed into application identifiers, and GTIN/EAN/UPC check-digit validation + GTIN-14 normalization.

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.ScanReceived += scan =>
    {
        var scannerService = /* resolve IHardwareScannerService */;
        scannerService?.OnScan(scan);
    };
}

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.ScanReceived — each ScanResult tells you the barcode, which transport delivered it (SerialPort, Broadcast, KeyboardWedge, External), and when.

Other scanner brands (broadcast intents)

Most non-RT150 handhelds (Zebra DataWedge, Honeywell, Urovo, budget vendors) broadcast scans as an intent. IntentScannerHost takes one or more IntentScannerProfiles - register several and one APK works on whichever device it lands on:

// Multi-device: whichever vendor's broadcast fires, wins
_scannerHost = new IntentScannerHost(this,
    IntentScannerProfile.Rt150,
    IntentScannerProfile.Urovo,   // byte[] payload + length extra handled
    new IntentScannerProfile      // Zebra DataWedge - action comes from your DataWedge profile
    {
        Actions = ["com.mycompany.ACTION"],
        DataExtraKeys = ["com.symbol.datawedge.data_string"],
        FormatExtraKey = "com.symbol.datawedge.label_type",
    });
_scannerHost.ScanReceived += scan => scannerService?.OnScan(scan);

Profiles support string extras (tried in order), byte-array extras with a length extra and configurable encoding (Chinese-market devices often use GBK), and an optional format/symbology extra that flows into ScanResult.Format. Any Context works as the host - Activity, Application, or a foreground Service for background scanning.

Same lifecycle wiring as Rt150ScannerHost (Start/Stop/Dispose). The single-action (context, action, extraKey) constructor still exists for the trivial case.

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(new ScanResult(code, ScanSource.KeyboardWedge));
    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.

GS1 / GTIN helpers

Server-side friendly (plain net11.0) — useful anywhere product barcodes are matched:

// GS1-128 element strings: (01) GTIN, (10) batch, (17) expiry, (21) serial...
if (Gs1Parser.TryParse(scan.Barcode, out var gs1))
{
    var gtin = gs1.Gtin;              // "04006381333931"
    var expiry = gs1.ExpiryDate;      // DateOnly, end-of-month and century rules applied
    var batch = gs1.BatchOrLot;
}

// Plain EAN/UPC/GTIN product codes
if (Gtin.TryNormalize(scan.Barcode, out var gtin14))
{
    // check digit verified; EAN-13/UPC-A/GTIN-14 variants all normalize to the same key
}

FNC1/GS separators (ASCII 29) and symbology prefixes (]C1, ]d2, ...) are handled. The AI table covers the common warehouse set; codes with unknown AIs fail parsing rather than guessing. A scan that fails both helpers is a custom/internal code.

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.