DualFlipClock Android

DualFlipClock Android is a native Android version of the dual flip clock app. It runs as a full-screen landscape clock, showing two independent time zones with local date and weather information.

The app is intentionally simple at runtime: it draws the clock UI directly with a custom Android View, keeps the screen awake, and stores the selected locations and layout mode in local preferences.

Downloads

• Android: Download DualFlipClock Android 1.1
• iOS: Download DualFlipClock on the App Store

Screenshots

Side-by-side clocks	Stacked clocks

Location picker

Video

Watch the stacked clock MP4

Features

• Full-screen landscape dual flip clock.
• Two display modes: side-by-side and stacked.
• Custom flip animation for changing digits.
• Black background with a deterministic star field.
• Primary clock defaults to Monterey.
• Secondary clock supports GPS location or a selected city/school.
• City, university, and high-school picker.
• Local search from the bundled cities.tsv data file.
• University and high-school acronym search.
• Local date and weekday display for each selected time zone.
• Weather icon and Celsius temperature using Open-Meteo.
• Weather refresh every 30 minutes.
• Night dimming from 23:00 to 07:00 in the secondary clock time zone.
• Screen stays awake while the app is running.

Data

Location data is bundled in:

app/src/main/assets/cities.tsv

Each row contains:

id    displayName    englishName    countryName    latitude    longitude    timeZone

The current Android app searches this local file only. It does not perform online city or school lookup during search.

Permissions

The app declares:

• INTERNET for Open-Meteo weather requests.
• ACCESS_FINE_LOCATION and ACCESS_COARSE_LOCATION for the secondary clock GPS option.

Location permission is only needed when the user chooses GPS for the secondary clock.

Build

Requirements:

• Android Studio with Android Gradle Plugin 8.5.2 support.
• JDK 17.
• Android SDK Platform 35.

Clone the repository, then open the project root folder in Android Studio:

DualFlipClockAndroid

Then run the app configuration on a connected Android device or emulator.

Project settings:

• Application ID: com.dualflipclock.app
• Minimum SDK: 19
• Target SDK: 35
• Compile SDK: 35
• Version: 1.0 / versionCode 1

Command-line debug build:

./gradlew assembleDebug

Debug APK output:

app/build/outputs/apk/debug/app-debug.apk

Install the debug APK to a connected device:

adb install -r app/build/outputs/apk/debug/app-debug.apk

Release Signing

Release signing is configured through a local keystore.properties file at the project root. This file must stay local and must not be committed.

You must create keystore.properties and the referenced signing key before running a release build.

Template:

storeFile=release-key.jks
storePassword=...
keyAlias=...
keyPassword=...

Release build:

./gradlew assembleRelease

Release APK output:

app/build/outputs/apk/release/app-release.apk

Files That Must Stay Local

Do not commit generated files, machine-local configuration, or signing secrets:

• local.properties
• keystore.properties
• *.jks
• .gradle/
• build/
• app/build/
• *.apk
• *.aab

Project Structure

app/src/main/java/com/dualflipclock/app/MainActivity.java
app/src/main/assets/cities.tsv
app/src/main/AndroidManifest.xml
app/build.gradle
settings.gradle

Most app behavior currently lives in MainActivity.java, including the custom clock drawing, picker UI, local city search, GPS handling, weather loading, and preference storage.