While the use of Python on Android has been made possible for some time now through SL4A, the Python for Android project has set out to make things even easier.  SL4A allows you to edit scripts and execute interactive interpreters directly on an Android device, but Python for Android can take a Python application and use it, in conjunction with the Android SDK/NSK, to create a single little Android APK file, including your application, libraries, and of course the Python code.

Produced through the Kivy organization as a way to support their framework (also called Kivy), a cross-platform open source library, Python for Android is currently equipped with only one Java bootstrap for decompressing the files within the APK.  Lighter bootstraps are currently in the works, but it could be some time before they reach consumers.

As it stands, Python for Android looks to be the most versatile tool yet for developing Python applications for the Android platform, with its biggest advantage being the self-contained binary files it creates that are so easy to install.  Mathieu Virbel provides a list of pros and cons for working with Python for Android:

Pros:

• A blacklist.txt file that can be used to exclude files in the final APK
• Reusable distribution for other applications
• Modular recipes architecture
  
  

Cons:

• You need a main.py file that will be used for starting your application
• Only one Java bootstrap available, using OpenGL ES 2.0
• Only Kivy toolkit is working.  I'm sure that other people can enhance it to add other toolkit recipes.  But for example, pygame is not going to work because the Android project is OpenGL ES 2.0: pyagme drawing will not work.
  
  

-- Mathieu Virbel

Another important factor to consider is that the code is currently being tested exclusively on Ubuntu 11.10 and only offers support for a few Python Modules including: pygame, kivy, android, sqlite3, and openssl.  However, more testing and greater support should become available in the following months.

For more in-depth information, including coding and plenty of useful examples, be sure to visit Virbel's GitHub page.