# Android Builder

A Docker image for building Android applications with Kotlin support. Includes Android SDK, build tools, and Java 17.

## Features

- **Debian Stable** base image
- **Java 17** (OpenJDK)
- **Android SDK** with latest command line tools
- **Android API 35** and Build Tools 35.0.0
- **NDK** support
- Network access for dependency downloads
- Ready for CI/CD pipelines

## Quick Start

### Using with Docker Compose

Create a `compose.yml` in your Android project:

```yaml
services:
  release:
    image: android-builder:latest
    network_mode: host
    volumes:
      - ./release:/release
      - .:/source
      - ./path/to/your/keystore.jks:/tmp/key.jks:ro
    environment:
      - KEYSTORE_PASSWORD=your_keystore_password
      - KEY_ALIAS=your_key_alias
      - KEY_PASSWORD=your_key_password
```

Run the build:
```bash
docker compose run --rm release
```

### Using with Docker Run

```bash
docker run --rm \
  --network host \
  -v $(pwd):/source \
  -v $(pwd)/release:/release \
  -v $(pwd)/keystore.jks:/tmp/key.jks:ro \
  -e KEYSTORE_PASSWORD=your_password \
  -e KEY_ALIAS=your_alias \
  -e KEY_PASSWORD=your_key_password \
  android-builder:latest
```

## Environment Variables

| Variable | Description | Required |
|----------|-------------|----------|
| `KEYSTORE_PASSWORD` | Password for your Android keystore | Yes (for signed builds) |
| `KEY_ALIAS` | Alias of the key in your keystore | Yes (for signed builds) |
| `KEY_PASSWORD` | Password for the specific key | Yes (for signed builds) |

## Volume Mounts

| Host Path | Container Path | Description |
|-----------|----------------|-------------|
| Your project root | `/source` | Android project source code |
| Output directory | `/release` | Where built APKs will be placed |
| Your keystore file | `/tmp/key.jks` | Android signing keystore (read-only) |

## Gradle Configuration

For signed builds, configure your `app/build.gradle.kts`:

```kotlin
android {
    signingConfigs {
        create("release") {
            storeFile = file("/tmp/key.jks")
            storePassword = System.getenv("KEYSTORE_PASSWORD")
            keyAlias = System.getenv("KEY_ALIAS")
            keyPassword = System.getenv("KEY_PASSWORD")
        }
    }
    
    buildTypes {
        release {
            signingConfig = signingConfigs.getByName("release")
            // ... other release config
        }
    }
}
```

## Build Process

The container will:
1. Make `gradlew` executable
2. Run `./gradlew assembleRelease`
3. Copy built APKs to `/release` directory

## Output

After building, you'll find your APKs in the mounted release directory:
- `app-release.apk` - Signed release APK (if keystore provided)
- Debug APKs (if building debug variants)

## Creating a Keystore

If you don't have a keystore yet:

```bash
keytool -genkey -v -keystore keystore.jks \
  -alias your_alias \
  -keyalg RSA \
  -keysize 2048 \
  -validity 10000
```

## Supported Android Versions

- **Target SDK**: 35
- **Min SDK**: Depends on your project
- **Build Tools**: 35.0.0
- **NDK**: 26.1.10909125

## Building the Image

```bash
docker build -t android-builder:latest .
```

## CI/CD Usage

This image is perfect for CI/CD pipelines. Example for Gitea Actions:

```yaml
jobs:
  build:
    runs-on: ubuntu-latest
    container:
      image: android-builder:latest
    steps:
      - uses: actions/checkout@v4
      - name: Build APK
        run: |
          chmod +x ./gradlew
          ./gradlew assembleRelease
        env:
          KEYSTORE_PASSWORD: ${{ secrets.KEYSTORE_PASSWORD }}
          KEY_ALIAS: ${{ secrets.KEY_ALIAS }}
          KEY_PASSWORD: ${{ secrets.KEY_PASSWORD }}
```

## Troubleshooting

### Network Issues
If you get `UnknownHostException`, ensure you're using `network_mode: host` in Docker Compose or `--network host` with Docker run.

### Permission Issues
The container runs as root. If you have permission issues with output files, you may need to adjust file ownership after build.

### Keystore Not Found
Ensure your keystore path is correct and the file exists on the host system before mounting.