Android-KTag-Apps/subapp-sample

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:

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:

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:

<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)