Python for Android : apk stuck on loading screen

I am trying to convert my python 3 code into an apk using Python-For-Android's tool. They have recently added python 3 support albeit it being experimental.

It may be of importance to note that my whole program is written in pure python and uses no kivy frameworks, it's graphical interface is all done in tkinter, no extra modules apart from the ones that already come python have been used.

I have compiled my programs (the user interface references the 'brains') stored in the following directiories

package
    __pycache__
    __init__.py
    Solver.py
main.py
__pycache__

with python-for-android and I've then got the resultant apk, this is on debian by the way, if it makes any difference, which I have installed, without any problems so far on my phone...

It's only when I launch the application, which has installed without problem that it goes to a white loading screen with loading in the top left corner but never gets past it

I read somewhere it's because of a Java error, I understand this may have been used to compile the programs...

My question, after all of this background stuff is how do I fix it as I don't know much about Java?

EDIT: I've ran this on a virtual machine and got an error... please see here

EDIT 2: Javac warnings whilst compiling