LifeTimer

An Android app that shows how much time has elapsed since — or remains until — any date and time you choose. All time units update live every ~10 milliseconds.

Features

• Pick any past or future date and time
• Displays total elapsed/remaining time in 8 units simultaneously: milliseconds, seconds, minutes, hours, days, weeks, months, and years
• Live updates every ~10ms
• SINCE / UNTIL indicator that flips automatically
• Supports light and dark mode (dynamic color on Android 12+)

Requirements

• Android Studio Hedgehog (2023.1.1) or newer
• JDK 17+
• Android device or emulator running API 26 (Android 8.0) or higher

Build & Run

Via Android Studio (recommended)

1. Clone the repo:

   git clone https://github.com/your-username/LifeTimerKotlin.git

2. Open Android Studio → File → Open → select the LifeTimerKotlin folder

3. Accept the Gradle wrapper download prompt and wait for sync to complete

4. Select a device or emulator (API 26+) and click Run

Via command line

# Debug build
./gradlew :app:assembleDebug

# Install directly to a connected device
./gradlew :app:installDebug

# Release build (requires signing config)
./gradlew :app:assembleRelease

The debug APK is output to app/build/outputs/apk/debug/app-debug.apk.

Project Structure

app/src/main/kotlin/com/example/lifetimer/
├── MainActivity.kt        # Compose UI (picker, direction badge, time unit cards)
├── MainViewModel.kt       # 10ms ticker coroutine + TimeState computation
└── ui/theme/
    ├── Color.kt           # Material 3 color tokens
    ├── Type.kt            # Typography scale
    └── Theme.kt           # Light/dark color schemes, dynamic color, edge-to-edge

Tech Stack

Concern	Solution
UI	Jetpack Compose + Material Design 3
State	ViewModel + StateFlow
Timer	Coroutine while(true) { delay(10L) } in viewModelScope
Time math	java.time.temporal.ChronoUnit (native at API 26+)
Build	Kotlin DSL + Gradle version catalog
Min SDK	26 (Android 8.0)
Target SDK	34 (Android 14)