kadence/android/README.md

Kadence for Android

The fourth client, for the Nothing Phone (3). Same backend, same editorial design, plus the three things only a native phone client can do: enforce the focus guard on the phone itself, surface the running interval as an Android 16 Live Update, and draw the timer on the rear Glyph Matrix.

Two modules, and why

Module	What it is	Needs the Android SDK?
core	Plain Kotlin on the JVM: the matchers, the policy clock, the timer maths, the outbox reconciliation, the Glyph frame renderer, the design tokens	No
app	The Android client: Compose UI, services, Room, the HTTP client, the Glyph toy	Yes

Everything with interesting behaviour lives in core, deliberately. The result is that the hard parts — offline reconciliation, glob and mask matching, the blocking policy, even the 25×25 rear display — are testable on a laptop with nothing but a JDK, with no emulator, no SDK and no phone in the loop:

make android-test          # both modules: 219 tests, no device, no backend
make android-test-core     # just the pure-logic suite: needs only a JDK

settings.gradle.kts only includes :app when an SDK is actually present, so that command works on a machine that has never seen the Android tooling.

Running the tests

./gradlew :core:test :app:testDebugUnitTest

219 tests, none of which need a device or a running backend. The backend lives only on the dev machine, so the suite feeds on committed JSON fixtures under app/src/test/resources/fixtures/ and a MockWebServer; there is no step that curls a live server.

:core (186 tests):

Suite	What it pins down
GlobTest	Python fnmatch parity — expectations generated from CPython, because the block lists are shared with the backend
BlockerTest	blocker_service.py parity: expand_entry, allow-list subtraction, the policy decision and its reason strings, schedule windows incl. midnight wrap
DomainMatcherTest / AppMatcherTest	hostname and app matching, allow-list precedence, and the masks a hosts file cannot express
NormalizeHostTest	what a browser URL bar actually hands over: bare hosts, full URLs, search phrases, chrome://, punycode
ReconcileTest	one test per row of the conflict matrix — another device taking over, our own replay landing, view-only mode
OutboxCoalesceTest / PostconditionTest / PartitionForReplayTest	the offline queue: coalescing, the at-most-once probes, and quarantining intervals that cannot be filed honestly
TickMathTest / DialGeometryTest	the countdown anchor and the dial's tick rule
Glyph*Test	the rear matrix, asserted as ASCII art
TokenParityTest	reads frontend/src/tokens.ts and lib/viz.ts and fails if a single colour channel drifts
AccentTest	the system-accent policy and its contrast guard

:app (33 tests, on the JVM via Robolectric):

Suite	What it pins down
DtoToleranceTest	every endpoint's fixture decodes — then decodes again with keys stripped, unknown keys added and nulls where values are declared. The backend has no response models, so this is the contract
KadenceApiTest	X-API-Token, the session cookie, 401 routing (and not routing on the login path), both FastAPI detail shapes, a 422 rendered as field: message, an unreachable server as a typed error
ThemeTest	the palette actually reaching a composable, and that the serif clock is genuinely fixed-advance

Toolchain

Gradle 9.6 (via the wrapper) on JDK 21 — newer JDKs are ahead of what AGP supports:

export JAVA_HOME=/usr/lib/jvm/java-21-openjdk

For the app module you also need an Android SDK. AGP 9.4 with Compose 1.12 wants compileSdk 37, which is published under Android's new minor-version scheme as platforms;android-37.0 (plain android-37 does not exist). targetSdk stays 36, because Android 16 is what the phone runs. Point the build at the SDK with ANDROID_HOME, or android/local.properties:

sdk.dir=/home/you/Android/Sdk

The Glyph Matrix SDK

glyph-matrix-sdk-2.0.aar is not on Maven — it has to be downloaded from Nothing's developer kit and dropped into glyph/libs/. It is git-ignored, and the Glyph code sits behind an interface with a no-op implementation, so a missing .aar disables the rear display and breaks nothing else. The renderer itself is in core and needs none of this to be tested.

Design notes

• Fraunces has no tabular figures. Its digits are proportional — 1 is 1024 units against 0 at 1461 — and the font ships no tnum feature, so the web app's global font-variant-numeric: tabular-nums does nothing for the serif dial clock. Here the clock goes through TabularFigures, which lays every glyph in a box as wide as the widest digit; ThemeTest measures it. Inter does ship tnum, so the sans numbers are fixed with a font feature instead.
• The canvas is Kadence's, the accent is the phone's. Warm paper, ink type, hairline rules and Fraunces figures are fixed; the single accent comes from Android's dynamic palette when available, falling back to the brand ember. onAccentArgb() picks the label colour by WCAG contrast, because a wallpaper-derived accent can be any lightness — that guard is what keeps "use the system colour" from producing unreadable buttons.
• Chart colours never follow the accent. They come from the validated, colour-blind safe palette in viz.ts. A chart has to stay readable; that is a property of the palette, not of the wallpaper.
• No VpnService, ever. Android allows exactly one, and it belongs to the user's always-on VPN. Website blocking reads the browser URL bar through an accessibility service instead; app blocking polls UsageStatsManager. Neither touches the VPN slot.
• The server owns the clock. The phone polls, ticks locally from a monotonic anchor, and re-anchors on every reply. Offline writes go to an outbox and the server's answer always wins the final word.

Verifying on the device

See the plan at ~/.claude/plans/make-an-app-for-logical-russell.md for the full manual script. The short version, once the SDK is installed:

make up                                   # backend + web UI on :8000
ip -4 addr show | grep inet               # find the LAN address for the phone
make android-install                      # ./gradlew :app:installDebug
adb logcat -s Kadence:*

Note that an always-on VPN can swallow a LAN address; adb shell curl -s http://<lan-ip>:8000/api/health is the first thing to check if onboarding cannot reach the backend.