Chaquopy
Chaquopy is a plugin for Android Studio's Gradle-based build system. It focuses on close integration with the standard Android development tools.
It provides complete APIs to call Java from Python or Python from Java, allowing the developer to use whichever language is best for each component of their app.
It can automatically download PyPI packages and build them into an app, including selected native packages such as NumPy.
It enables full access to all Android APIs from Python, including the native user interface toolkit (example pure-Python activity).
This is a commercial product, but it's free for open-source use and will always remain that way.
(I am the creator of this product.)
