Kivy – Open-source Python library for rapid development of applications

No, kivy has no relation to libnui.

Others have noted that this should not happen, but just to comment on the specifics; the size of a plain APK like a Hello World should be just 6-7MB. Anything else is files in the project path that haven't been excluded (e.g. big images in the project directory) or dependencies that the python-for-android tools have been instructed to include. I don't know what went wrong for you, but that size is highly atypical, and if you're ever interested we can help debug it.

It's possible to reduce the size further, one of our devs has recently been experimenting about this in particular and I think has got down to 4MB without too much difficulty. The problem is that reducing it much further starts to mean being more careful about blacklisting stuff like modules in the python standard library, which can be hard to do automatically without breaking dependencies. It's highligted some potential optimisations in kivy's internals though, so maybe we can make it easier to leave out some non-essential kivy components.

Just to be clear about the build time thing, compiling python + project dependencies may take a few minutes (e.g. your 15 minute figure), but subsequent builds don't need to repeat this and will take just a few seconds.

2048 app that use Kivy on android https://play.google.com/store/apps/details?id=com.meltingroc...

It compiles the python interpreter for android/arm, then bundles this all together in an APK - along with much of the standard library and any extra modules the user wants. It also includes a java bootstrap app that interacts with the system, but does essentially nothing except initialise and display an opengl surface that kivy renders to - along with running the python interpreter on the user's kivy code.

This bootstrap is invisible to the user, you don't need to touch the java to use kivy. That said, kivy has some cool sister projects for using the normal java api - pyjnius for accessing java classes directly from python, and more recently plyer to provide a more pythonic wrapper to common things like vibration, sensors etc.

(The above is also mostly the same for the ios build process).

> Is it better than PhoneGap etc and closer to native apps?

I would say more that it is just different, with advantages and disadvantages of its own. It doesn't use native widgets (though it's possible to create and use them in some ways with pyjnius), so it isn't different in this sense.

I've always been confused about open-source projects that go big on marketing themselves.

Building a good community around open-source projects holds obvious advantages as you'd always need contributors to push the project through its future generations.

As far as I can see, Kivy is supported by a group of independent developers. Kivy (as a group) must have spent money in marketing the product, launching developer contests, publishing books on Kivy (I've seen a couple books on Kivy by O'reilly), and other stuff. I'm just curious to know in what other ways, apart from the need to grow the community around your project, does marketing your open-source project help? And is the money put into marketing the project contributed by the creators themselves?