This folder contains an Android app that can compile Wear OS watch faces as .apk or .aab at runtime.

It does so by using a custom Rust library depending on pack-api, plus a Java class which interfaces with that library (PackPackage.java).

Note that this example is a phone app, but the concept should work just as well on Wear OS.

Tested on macOS, should work on Linux with minimal modification.

• Install and set up cargo
• Install the Android SDK and NDK.
• rustup target add aarch64-linux-android
• rustup target add x86_64-linux-android
• rustup target add armv7-linux-androideabi
• Copy pack-java/.cargo.example to pack-java/.cargo and update the paths there to the correct ones
• Run ./generate-testing-pem.sh and copy its output
• Place its output in StaticExampleData.java 's COMBINED_PEM_STRING field
• Run ./provide-libraries-to-java-project.sh
• Open ./PackFromJava in Android Studio and press the run button

Note: That step about running generate-testing-pem is very important! This repo ships with its PRIVATE KEY removed - you should generate your own and not share it with anyone. The app crashes if you don't insert a working private key from this step.

You should be presented with a phone activity that says "Compile an APK on-device" and upon clicking that button, you'll get a save file dialog for output.apk.

You can look into MainActivity.java for how this package is compiled.

If you need to, you could modify PackPackage.java to create a more idiomatic API, but theoretically you could leave it untouched if this example API doesn't bother you.

This is sample code, it isn't up to scratch, quality-wise, with the rest of the repo. For example, it does not handle errors. It's intended to give a taste of what it could be like to use Pack on Android. Please modify it to suit your needs.