Since the app is still in testing phase there is not yet a full integration with the Google Play store. To run the app one has to go to http://www.jekejeke.ch/ and obtain a license. We hope we can resolve the inconvenience soon. The activaition is seen in screenshot 7.
The extension has been tested with earlier smartphones running Android 2 (Froyo) and with newer tablets running Android 4 (Ice Cream Sandwich). Bug reports and feature requests can be sent to firstname.lastname@example.org . The screenshots 1-2 show the extension in action (Pythogarean Triples, Mini Isabelle Clone).
The module.apk cannot be directly embedded. One has to obtain module.zip from the web site at http://www.jekejeke.ch/ to be able to compile the application. The same web site can be used to download Swing versions. The website also contains the source text of those parts that are open.