Kivy is an open source Python library for the rapid development of cross-platform user interfaces. Kivy applications can be developed for Linux, Windows, OS X, Android and iOS using the same codebase.
Graphics are rendered via OpenGL ES 2 rather than through native widgets, leading to a fairly uniform appearance across operating systems.
Developing interfaces in Kivy optionally involves the use of kvlang, a small language that supports python-like expressions and python interop. The use of kvlang can drastically simplify the development of user interface as compared to using Python exclusively.
Kivy is free to use (currently under the MIT license), and professionally backed.
This is a big issue in Kivy, Python, and many programming languages
When one resource is required by two files, it is normal to place this resource in the file that will be using it most. But if this happens with two resources, and they end up in opposite files, then importing both into Python will result in a circular import.
Python will import the first file, but this file imports the second. In the second, this imports the first file, which in turn imports the second and so on. Python throws the error ImportError : cannot import name <classname>
This can be solved by using a third file, and importing this third file into the first two. This is resources.py in the second example.