Dro 🕰

დრო (dro — Georgian for "time") — a small Android app for people whose day is spread across time zones: a live clock for each city you care about, a working-hours overlap strip that shows when everyone is actually at their desk, and a home-screen widget that keeps ticking without waking the phone.

No accounts, no network, no analytics. Time zones come from the platform's own tz database.

Why this app exists

I live in Tbilisi and work with a team that is rarely in the same time zone as I am. The question I ask several times a day is not "what time is it in X" but "when today can I reach X during their working hours, and what does that cost me in mine?" Generic world clocks answer the first question; Dro is built around the second.

(A small irony behind the name: the two cities I move between, Tbilisi and Dubai, are both UTC+4 all year — the original "dual clock" idea was a no-op, so the app grew into the overlap finder it should have been from the start.)

Screenshots

Clocks	Overlap + preview	Widget	Dark

Features

• 🏠 Home + cities — pick a home zone and any number of others. Each row shows the local time, a tomorrow / yesterday badge when the date differs from home, and the offset relative to home (+5h, -1h 30m). Change home from any row and every offset re-bases.
• ⏱ Live — clocks tick on the wall-clock minute boundary (the delay is "until the next :00", not a fixed 60 s), only while the screen is visible. Honours the device 12/24-hour setting.
• 🗓 Working-hours overlap — a 24-hour bar per city (default 09:00–18:00 local, editable, overnight shifts allowed) laid out on the home zone's axis, with the window where everyone is at work drawn across all bars and summarised as "Everyone's working 12:00–13:00 your time". A city whose day straddles home midnight shows as two segments; half-hour zones, and 23/25-hour DST days in the home zone, are handled and unit-tested.
• 🎚 Time scrubber — press or drag on the bars to preview any moment: every clock re-reads at that instant, a chip names the previewed time, tap it to return to now. Pick a time opens a dialog for the same thing without a gesture.
• 📱 Widget — a classic RemoteViews app widget built on TextClock, one per zone with its own timeZone. The system keeps the clocks current itself: updatePeriodMillis is 0, the app schedules no alarms, no WorkManager, no wakeups. Glance can't express a self-ticking clock without periodic updates, so this is one of the places the old API is the right one. Re-rendered when the city list changes; Add widget to home screen in the app uses the Android 8 pin flow.
• 🔒 Private by design — preferences only (DataStore); the app declares no permissions and never touches the network. Time zones come from the platform tz database.
• ♿ Accessible — each clock row reads as one sentence ("Tokyo, 12:23 am, 5 hours ahead, tomorrow"), each bar as "London works 9:00 am–6:00 pm local, 12:00 pm–9:00 pm your time", row actions are menu items rather than gestures, and the scrubber has a dialog equivalent.
• 🎨 Material 3 — dynamic color, light/dark, edge-to-edge.

Architecture

domain/   pure Kotlin, 54 unit tests — ZoneClock (local time / day shift / offset label),
          ZoneCatalog (tz database → searchable cities), WorkingHours + OverlapFinder
          (shared window on the home-day axis), Settings + SettingsCodec, TimeFormat
data/     DataStore preferences: home zone, city list, working-hours overrides
ui/       Compose — clock list, add-city sheet, overlap strip + scrubber, hour dialogs
widget/   RemoteViews + TextClock app widget

Pure logic never touches Android: everything under domain/ is java.time and plain Kotlin, tested with JUnit against fixed instants — including the London spring-forward and fall-back days, where the home day is 23 or 25 hours long and the strip's axis is elapsed minutes rather than wall-clock so it stays linear.

Building

./gradlew :app:assembleDebug :app:testDebugUnitTest

Kotlin 2.3, AGP 9, Compose BOM 2026.06, minSdk 26.

License

MIT © 2026 Merab Kochlamazashvili