Android Integration

Skotch can produce unsigned Android APKs containing DEX bytecode and a generated binary AndroidManifest.xml. No Android SDK, Gradle, or d8 is required.

Project setup

myapp/
  build.gradle.kts
  src/main/kotlin/
    Main.kt

build.gradle.kts

plugins {
    id("com.android.application")
    kotlin("android")
}

android {
    namespace = "com.example.myapp"
    compileSdk = 34

    defaultConfig {
        applicationId = "com.example.myapp"
        minSdk = 24
        targetSdk = 34
        versionCode = 1
        versionName = "1.0"
    }
}

Building

skotch build

Output: build/app-unsigned.apk

The APK contains:

File	Source
AndroidManifest.xml	Generated from the android { } config (binary AXML format)
classes.dex	Compiled from src/main/kotlin/ sources

APK signing

Caution

The APK is unsigned by default. You must sign it before installing on a device or submitting to the Play Store.

Skotch supports APK Signature Scheme v2 with PEM key files. Add a signing config to your build file:

android {
    signingConfigs {
        debug {
            storeFile = "keys/debug-key.pem"
            storePassword = ""
            keyAlias = "debug"
            keyPassword = ""
        }
    }
}

Note

Only RSA-PKCS1-v1.5 with SHA-256 is supported. PKCS#12 keystores (.jks, .keystore) are not yet supported — convert to PEM format.

Configuration defaults

If not specified in build.gradle.kts:

Property	Default
minSdk	24
targetSdk	34
compileSdk	34

Current limitations

Caution

Skotch’s Android support is early-stage. The following features are not yet available.

Feature	Status
Android resource processing (res/)	Not supported
Source AndroidManifest.xml parsing	Manifest generated from build config only
Android SDK APIs	Not available (no classpath/dependency support)
Activity, Fragment, View classes	Blocked on class support
ECDSA / Ed25519 signing	Only RSA supported
PKCS#12 keystores	Not yet — use PEM
resources.arsc generation	Not yet — only included if already present
ProGuard / R8 shrinking	Not supported
AAB (Android App Bundle)	Not supported

Single-file DEX compilation

For experiments, you can compile a single .kt file to DEX directly:

skotch emit --target dex hello.kt -o classes.dex

Verify the output with Android SDK tools if available:

dexdump -d classes.dex