There's lots of code here and includes the use of the Philips Http Library. The code posted above will be untestable by others without having that exact library.

A few recommendations if I may.

1) Did you add the Http library in PEP2 at the activity level?
2) What is the version of the Http library? Is it one you received from me earlier or did you download it from some other configuration?
3) Where does all this script reside? I'm assuming you put it into a Page.
4) I see references to many widgets. Are all of these panels on the same page?
5) As a reminder, script is good for example but if you want others to be able to run, you need a working reference. Do you have a small XCF file that you'd be willing to share?

Do you have a reference to the JSONRPC docs for Kodi?
I found these.

[Link: kodi.wiki]
[Link: kodi.wiki]

It mentions many version of Kodi and which Version of the API are you using?
The link above also mentions pretty-printing of the JSONRPC.

I see you configured port 9090 (default). I think out of the box, JSONRPC endpoint is turned off. What did you have to do to enable this? Did you also turn on pretty-printing?

All your JSON code for getNumber, getString, getObject functions works only if your 'key' is unique. Does Kodi return a list of tracks or other things which might be represented as an array of objects with the same keys (field names)? Methods like Playlist.GetItems or AudioLibrary.GetSongs likely meet this condition. Once you start using these methods, I think you will determine that
When you get to this point, I think a JSON Library will better serve you here.

I ask all these things because I've never played with Kodi. Maybe I should go setup a small system with it.

Would it be possible for you to provide a small writeup of the installation process of Kodi, the platform, etc?

If you want to connect offline, that's fine too. Let me know.

Thanks,
Lyndel