Hacker Tracker

Android conference companion for schedules, maps, news, and more.

Companion apps: iOS · Web

Stack

• Kotlin, Jetpack Compose, Material 3
• Firebase (Firestore, Auth, Messaging, Crashlytics, Analytics, Remote Config)
• Koin, Coroutines, Navigation Compose, WorkManager

Architecture

The app uses a pragmatic MVVM + repository layout across Gradle modules. Data flows like this:

Compose screen → ViewModel → repository → :data interface
  → Firebase / Retrofit implementation → :core model → Flow → UI

• :core — shared domain models, utilities, and typed local storage. No project dependencies.
• :data — backend-neutral data-source interfaces, UserSession, and local bookmark implementations. Depends on :core.
• :ui — shared Compose screens and components used across features. Depends on :core and :feature-glitch.
• :app — composition root: DI aggregation, navigation, schedule/shell repositories and ViewModels, and screen wiring. Depends on every module.

User-facing feature modules typically own their repository, ViewModel, UI, and Koin module. Navigation graphs and Firebase/Retrofit bindings stay in :app.

Dependency graph

:core
├── :data
├── :feature-glitch ──→ :ui
├── :feature-play
├── :feature-analytics
├── :feature-reminder          (:core + :data)
├── :feature-retrofit          (:core + :data)
│
:feature-firebase              (:core + :data + :feature-play)
│
:data + :ui
├── :feature-locations
├── :feature-merch             (+ :feature-glitch)
├── :feature-documents
├── :feature-feedback
├── :feature-organizations
├── :feature-wifi
│
:app → all of the above

Foundation

Module	Role
core	Domain models (Conference, Event, Speaker, …), shared state types, OkHttp client, notifications, typed stores (MerchCartStore, UserPreferencesStore, ContentSyncStore, OfflineQueueStore)
data	Data-source contracts (ContentDataSource, LocationsDataSource, …), UserSession, plus local bookmark stores
ui	Reusable Compose screens/components (schedule, home cards, maps chrome, settings, filters, privacy policy) and shared UI state types

Infrastructure (feature-*)

Module	Role
feature-firebase	Primary backend: Firestore data sources, DTO → core mapping, anonymous auth / conference session
feature-retrofit	HTTP maps download/cache (MapsDataSource)
feature-analytics	Analytics events and Remote Config flags
feature-play	In-app updates and Play Age Signals
feature-reminder	WorkManager-based event/feedback reminder notifications
feature-glitch	Visual/easter-egg effects consumed by :ui and :feature-merch

User-facing features

Module	Role
feature-locations	Location tree browser (repo, ViewModel, screen, Koin module)
feature-merch	Merch catalog, per-conference cart, and order-summary QR
feature-documents	Conference document list/detail (repo, ViewModel, screen)
feature-feedback	Feedback form UI, HTTP feedback submission, and content reporting
feature-wifi	Wi-Fi join helpers and screen (repo, ViewModel, Koin module)
feature-organizations	Org list/detail (repo, ViewModels, screens, Koin module)

Composition root (app)

App initializes Firebase, Timber, and Koin via appModules(). That list aggregates:

• App modules — shellModule (prefs/cart/bookmarks/analytics shell), firebaseDataModule (:data interfaces → Firebase/Retrofit), scheduleModule / settingsModule (schedule-shell repos and ViewModels), playModule
• Feature modules — locationsModule, productsModule, organizationsModule, wifiModule, feedbackModule, documentsModule, reminderModule

MainActivity owns the root NavHost; route wrappers in :app collect ViewModel state and pass it into :ui or feature screens. Feature modules do not register their own navigation graphs.

Schedule, search, home, news, FAQ, maps, speakers, and filters remain in :app (not extracted as feature modules).

Requirements

• Android Studio Quail 2 (2026.1.2) or newer (AGP 9.3)
• JDK 17
• minSdk 26 / targetSdk 36 / compileSdk 37

Firebase config is not checked in. Copy the example and replace placeholders with values from the Firebase console (Project settings → Your apps):

cp app/google-services.json.example app/google-services.json

Optional — content reporting endpoint (used by :feature-feedback; CI can inject the same via REPORT_URL):

# local.properties
REPORT_URL=https://your.endpoint/report

Without it, the build uses a placeholder URL and report submission will fail at runtime.

Build

./gradlew :app:assembleDebug

Install on a device or emulator:

./gradlew :app:installDebug

Testing

Unit / CI

./gradlew ciCheck

Runs ktlintCheck, unit test, :app:lintDebug, and :app:assembleDebug (same as CI).

Maintainer smoke test

Manual checklist for DC34 → DC33 → TEST (home menu walk, conference switch, merch QR / cart isolation): docs/SMOKE_TEST.md.

TalkBack / content labels / custom control roles: docs/ACCESSIBILITY.md.

Live-Firebase Compose instrumentation (device/emulator + google-services.json required; not PR-gated):

./gradlew :app:connectedDebugAndroidTest