# 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 10 seconds. Once the timer reaches zero, the app plays a system error tone and closes the dialog. This project serves as a basic example of using `CountDownTimer`, `ToneGenerator`, and custom `Dialog` implementation in Android.

## Key Features
- **Single-Action Interface**: A simple main screen with a start button.
- **Modal Countdown**: A non-cancelable dialog that prevents user interference during the countdown.
- **Audible Alert**: Integration with Android's `ToneGenerator` to play `TONE_SUP_ERROR` upon completion.
- **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
1. Open the project in Android Studio.
2. Select your target device/emulator.
3. Click the **Run** button or press `Shift + F10`.

## Project Structure
```text
app/
├── src/
│   └── main/
│       ├── java/com/example/countdowntimer/
│       │   ├── MainActivity.kt      # Main entry point; launches the timer
│       │   └── CountdownDialog.kt   # Logic for the 10s countdown and tone
│       ├── res/                     # UI layouts and resources
│       └── AndroidManifest.xml      # Application manifest
└── build.gradle                     # App-level build configuration
```