A simple Android Overlay template, provided as is with no guarantee that it'll ever work.
You will need to install apktool to compile it, simply run apktool b app, then head over to the dist folder where you'll find the apk you've generated.
Provide a name for the apk beforehand in apktool.yml, and don't forget to fill in the blanks in AndroidManifest.xml.
You will also need to sign the apk before being able to install it on your device.