# Countdown Timer

A minimal Android application that demonstrates a simple countdown functionality with an audible alert.

## Description
The Countdown Timer app is a lightweight utility that launches a modal dialog to count down from a user-selected duration (5s, 10s, 15s, or 30s). Once the timer reaches zero, the app plays a confirmation tone and vibration, then shows a dismiss button. This project serves as a basic example of using `CountDownTimer`, `ToneGenerator`, and custom `Dialog` implementation in Android.

## Key Features
- **Selectable Duration**: A main screen with a duration picker (chip group) and a start button.
- **Modal Countdown**: A full-screen dialog with circular progress ring, stop/restart buttons, and a confirmation tone during the final 3 seconds.
- **Haptic Feedback**: Vibration on the last 3 seconds and on completion (configurable via shared preferences).
- **Real-time Updates**: UI updates every second to reflect the remaining time.

## Getting Started

### Prerequisites
- Android Studio (Ladybug or newer recommended)
- JDK 17
- An Android device or emulator running API level 24 or higher.

### Building the App
To build the debug APK from the command line:
```bash
./gradlew assembleDebug
```

### Running the App

#### Via Android Studio
1. Open the project in Android Studio.
2. Select your target device/emulator.
3. Click the **Run** button or press `Shift + F10`.

#### Via ADB
First, ensure your device or emulator is connected (`adb devices`). Then install the debug APK and launch the app:

```bash
# Install the debug APK
adb install -r app/build/outputs/apk/debug/app-debug.apk

# Launch the app
adb shell am start -n com.example.countdowntimer.debug/com.example.countdowntimer.MainActivity
```

#### Taking a Screenshot via ADB
To capture a screenshot of the app from your host machine:

```bash
# Take the screenshot on the device
adb shell screencap -p /sdcard/screenshot.png

# Pull it to your host machine
adb pull /sdcard/screenshot.png screenshots/
```

## Project Structure
```text
app/
├── src/
│   └── main/
│       ├── java/com/example/countdowntimer/
│       │   ├── MainActivity.kt          # Main entry point; duration picker and timer trigger
│       │   ├── CountdownDialog.kt       # Countdown logic, tone, and vibration
│       │   └── CountdownCanvasView.kt   # Custom circular progress ring view
│       ├── res/layout/                  # UI layouts
│       │   ├── activity_main.xml
│       │   └── dialog_countdown.xml
│       └── AndroidManifest.xml          # Application manifest
└── build.gradle                         # App-level build configuration
```