# KTag Sample Subapp

A minimal Jetpack Compose subapp template for creating new KTag applications.

## Overview

The Sample subapp provides a starting point for creating new subapps in the KTag ecosystem. It demonstrates the minimal required structure and can be copied as a template for new functionality.

## Architecture

The simplest possible subapp structure:

```
┌─────────────────────────────────────────────────────────┐
│                   SampleActivity                        │
│                  (Compose Host)                         │
│  • Single "Hello World" screen                          │
└─────────────────────────────────────────────────────────┘
```

## File Structure

```
src/main/java/club/clubk/ktag/apps/sample/
├── SampleActivity.kt       # Main activity with Compose UI
├── SampleSubApp.kt         # Subapp registration
└── SampleInitializer.kt    # Startup initializer
```

## Creating a New Subapp

To create a new subapp based on this template:

1. **Copy the module**: Duplicate `subapp-sample` directory
2. **Rename the package**: Update package name in all files
3. **Update build.gradle.kts**: Change namespace
4. **Register the subapp**: Update `SampleSubApp` with new ID, name, icon
5. **Add to settings.gradle.kts**: Include new module
6. **Add dependency**: Include in main app's dependencies

## Required Components

### SubApp Interface

Every subapp must implement the `SubApp` interface:

```kotlin
class MySubApp : SubApp {
    override val id = "myapp"           // Unique identifier
    override val name = "My App"        // Display name
    override val icon = R.drawable.ic_myapp  // Launcher icon

    override fun createIntent(context: Context): Intent {
        return Intent(context, MyActivity::class.java)
    }
}
```

### Initializer

Register the subapp at startup:

```kotlin
class MyInitializer : Initializer<Unit> {
    override fun create(context: Context) {
        SubAppRegistry.register(MySubApp())
    }

    override fun dependencies(): List<Class<out Initializer<*>>> = emptyList()
}
```

### AndroidManifest.xml

Declare the activity and initializer:

```xml
<activity android:name=".MyActivity" android:exported="false" />

<provider
    android:name="androidx.startup.InitializationProvider"
    android:authorities="${applicationId}.androidx-startup">
    <meta-data
        android:name=".MyInitializer"
        android:value="androidx.startup" />
</provider>
```

## Optional Features

For more complex subapps, consider adding:

| Feature | Reference |
|---------|-----------|
| Settings | See `subapp-koth` or `subapp-medic` |
| MQTT | Implement `SettingsSubApp` interface |
| BLE | See `subapp-bletool` or `subapp-koth` |
| USB Serial | See `subapp-terminal` |
| ViewModel | See `subapp-koth` or `subapp-medic` |

## Dependencies

- Jetpack Compose (Material3)
- AndroidX Startup (for initialization)