SunZones

Track sunrise, sunset and daylight across multiple locations around the world. A minimal, single-screen Android app with time-aware gradient backgrounds, animated sun/moon arcs, and a yearly daylight chart.

Screenshots

Features

• Multi-location tracking -- swipe between saved locations to see real-time sun and moon data; tap page indicator to manage cities
• Sunrise & sunset times with day/night length and countdown to next sunrise
• Animated sun/moon arc -- a visual progress indicator showing where the sun (or moon) is in its path across the sky
• Moon phase & illumination -- current lunar phase emoji and illumination percentage
• Local time, labelled -- each card and city-list row says whose clock it is showing ("19:00 local time · 7 h ahead of you") and flags when the date over there is already different
• Time-of-day gradients -- card backgrounds shift dynamically through sunrise, morning, midday, afternoon, sunset, twilight and night palettes
• Resizable home-screen widget -- three designs from a 2x1 strip to a 4x4 block, each with a full-width sun/moon arc as its horizon line
• Timezone-aware -- each location stores its own IANA timezone, so times are always correct regardless of where your device is
• Search or GPS -- add locations by city name search or use your current position
• Sunrise/sunset reminders -- optional local notifications, scheduled entirely on-device
• 20 languages -- English, Polish, Chinese, Hindi, Spanish, French, Arabic, Bengali, Portuguese, Russian, Urdu, Indonesian, German, Japanese, Nigerian Pidgin, Marathi, Telugu, Turkish, Tamil, Vietnamese

SunZones Pro

A single one-time purchase (premium_lifetime, Google Play Billing -- no subscription, no ads, no account). The free tier holds three locations and every core sun feature above.

• Unlimited locations
• Twilight & light -- golden hour, blue hour and the full civil/nautical/astronomical twilight timeline
• Night & Moon -- moonrise and moonset, the astronomical-night window, how much of it is moonless, the next new moon, and whether the Milky Way core clears the horizon after dark
• Yearly daylight chart -- month-by-month day length, tap a month to jump to it
• Time travel -- step the date back and forward, or pick any day between 1900 and 2100, and every reading on the card follows
• Golden hour reminders

Privacy

No account, no backend, no analytics SDK, no ads. Sun and moon maths run entirely on-device; saved places never leave it.

One exception, stated up front: crash reports are sent to Google's Firebase Crashlytics, on by default, and can be turned off in Settings -> Diagnostics. Coordinates, saved place names and device identifiers are stripped from the message, breadcrumbs and custom keys before anything is sent; the stack trace and Crashlytics' own device/installation metadata are what remain.

All three store-facing documents are current: the privacy policy and Data Safety form were republished on 2026-07-30, and the store listing was rewritten on 2026-08-20 (see Plans/GROWTH.md).

Architecture

Clean MVVM, single-activity Jetpack Compose app with Hilt dependency injection.

Room DB (Flow)
  -> LocationDao -> LocationRepository -> GetLocationsUseCase(date, includeAstro)
       -> CalculateSunTimesUseCase (+ CalculateAstroNightUseCase) -> SunLocation
            -> MainViewModel (StateFlow) -> Compose UI
                                         -> WidgetRenderData -> Glance widget

Layer	Responsibility
data/local	Room entity, DAO, database
data/repository	Thin DAO wrapper, current-location replacement logic
data/preferences	DataStore: notification settings, crash-reporting opt-out
domain/usecase	Sun/moon calculations via commons-suncalc, astronomical night and Milky Way season, yearly daylight aggregation
domain/model	SunLocation (computed fields), AstroNight, ArcState (the one day/night decision), MonthDaylight
domain/util	Timezone-id hardening, administrative-suffix stripping for geocoded names
diagnostics	Crash-report scrubbing (pure JVM) + the Crashlytics seam behind it
billing	EntitlementRepository, Play Billing data source, monetization config/killswitch
ui/main	HorizontalPager of SunCard composables, date bar, 60-second auto-refresh; SelectedDatePolicy validates the restored/intent-borne date
ui/widget	Glance widget; layout breakpoints, element gating and bitmap arcs decided in pure functions outside the Glance tree
ui/addlocation	Geocoder search + GPS, timezone resolution via Android ICU
di	Hilt modules providing Room, DAO, Geocoder, FusedLocationProviderClient, billing and diagnostics

Tech stack

Language	Kotlin
UI	Jetpack Compose, Material 3
DI	Hilt
Database	Room (schema exported, migrations tested)
Preferences	DataStore
Widget	Jetpack Glance 1.1.1
Background work	WorkManager
Billing	Google Play Billing 9.1.0
Crash reporting	Firebase Crashlytics (opt-out; no Firebase Analytics)
Sun/moon math	commons-suncalc 3.11
Location	Google Play Services FusedLocationProviderClient
Geocoding	Android Geocoder
Timezone lookup	android.icu.util.TimeZone (built-in)
Tests	JUnit 5, MockK -- 391 JVM unit tests
Min SDK	26 (Android 8.0)
Target SDK	36 (Android 16)

Build

Requires Java 17 and the Android SDK.

A google-services.json for the Firebase project must be present at app/google-services.json -- it is committed, since this repository is private.

export JAVA_HOME="/opt/homebrew/opt/openjdk@17/libexec/openjdk.jdk/Contents/Home"
./gradlew assembleDebug

Full gate:

./gradlew lint testDebugUnitTest assembleDebug

assembleRelease now uploads the R8 mapping file to Firebase, so a release build needs network access. Debug builds upload nothing.

License

MIT -- Pawel Orzech