LaWallet Card Manager

Native Kotlin + Jetpack Compose Android app to activate LaWallet NFC cards on the ZCS Z92 POS terminal. Sign in with a device-token QR, tap a card, and it mints a one-time activation QR that prints on the built-in thermal printer for the end user to scan and claim the card. Reuses the ZCS SmartPos printer driver and NFC stack from ../android-pos-wrapper.

Features

• JWT login — scan (or paste) a device-token QR; the token's apiUrl claim picks the instance, every call is Bearer-authenticated, a 401 logs out.
• Live activation — tap → GET /api/cards/:id → real status / lightning address / design, then mint POST …/activation-tokens → print the QR.
• Real NFC + real thermal print on the ZCS hardware; the printed QR is the exact same ZXing code shown on screen.
• Settings — instance, pubkey, scopes, token expiry, an auto-print on tap toggle (mint + print automatically), log out, and the app version.
• Blank-card guidance — a tag with no LaWallet lnurl prompts to install it first with the LaWallet Card Installer app (on zapstore).
• Optimized release — R8 + resource shrinking + baseline profiles (~3.7 MB), signed. See PUBLISHING.md.

Toolchain

AGP 8.7 · Gradle 8.11 · Kotlin 2.0 · compileSdk 35 · minSdk 24 · targetSdk 35. Gradle needs JDK 17+ (e.g. Android Studio's bundled JBR).

Build / install / run

export JAVA_HOME="/Applications/Android Studio.app/Contents/jbr/Contents/Home"
./gradlew :app:assembleDebug      # build the debug APK
./gradlew :app:installDebug       # install on the connected Z92 (adb)
adb shell am start -n io.lawallet.cardactivation/.MainActivity

First launch asks for READ_PHONE_STATE (the ZCS SDK reads device identity during sdkInit). For a signed release build + zapstore publishing, see PUBLISHING.md.

How it works

1. Scanning — always armed for NFC; an animated radar pulse waits for a tap. ("Enter manually" pastes a card URL/id for testing.) A tapped tag with no LaWallet lnurl shows a blank card prompt instead.
2. Loading — a Lottie animation while GET /api/cards/:id runs (the id is parsed from the tapped …/api/cards/<id>/scan URL).
3. Card detail — a 3D floating card (real design.imageUrl via Coil) with the card status and lightning address; ACTIVATE / Cancel.
4. QR + print — ACTIVATE mints POST /api/cards/:id/activation-tokens {qrKind:"ONE_TIME"}; the returned qrPayload shows as a thermal-ticket preview that slides up (~2 s) while it really prints, then returns to scanning.

Testing the full flow needs a valid device-token JWT and a registered card on a reachable instance.

Look & feel

Themed after lawallet.io: near-black #0A0A0A canvas with a soft teal glow, a green status bar, the emerald-teal gradient #00836D → #00A085 → #00C7A0 on buttons, and Inter typography. The QR scanner is a portrait square reticle; the print preview is an actual thermal-ticket mock with torn-paper edges. Theme + brand helpers live in ui/theme/{Theme,Brand}.kt.

Drivers (reused vendor binaries)

• app/libs/SmartPos_1.9.4_R250117.jar — ZCS SmartPos SDK (com.zcs.sdk.*).
• app/src/main/jniLibs/{armeabi-v7a,arm64-v8a}/{libSmartPosJni,libEmvCoreJni}.so — required native libs; without them Sys.sdkInit() NPEs. The Z92 is 32-bit (armeabi-v7a).

Architecture

• pos/ZcsPrinter.kt — SDK init + printActivation(url) via DriverManager.getInstance().getPrinter() → setPrintAppendString / setPrintAppendBitmap (prints the same QrBitmap ZXing QR) / setPrintStart().
• pos/CardNfc.kt — NDEF parse (URI + Text), preferring the LaWallet lnurl record.
• MainActivity.kt — Compose host + NFC foreground dispatch; emits card URLs / a blank-card signal to SharedFlows.
• data/{Jwt,AuthStore,Api,Settings}.kt — JWT decode + token/prefs stores + the authenticated OkHttp client (Bearer, 401 → logout, apiUrl-derived base URL).
• util/Domain.kt — host extraction for the slip footer.
• ui/ — HomeScreen (scanning → loading → detail → QR/print state machine), LoginScreen (+ QrCaptureActivity portrait scanner), SettingsScreen, QrBitmap, and components/ (FloatingCard, PrintTicket, NfcPulse).