I created a simple combat simulator to get experience with developing GUIs in Python. I intended to show this to a local group of Python developers, and chose tkInter as the application's UI library because it ships with Python on Linux/Windows, so no additional installation is required for other users to install and run the application.

The application has two UI states: UNIT_INPUT and COMBAT.
The application starts in the UNIT_INPUT state, where users can add/edit/delete units from the simulation (see below). Users can also run a simulation in "headless mode", which will simulate 1,000 battles and display the attackers' chance of winning the battle.

Once the user is satisfied with the units specified, they move to the COMBAT state by pressing Enter. In this state, the simulation will run in real-time until the battle is finished, and users have the option to change simulation speed and pause the battle. A demo of the combat simulation can be seen below.

Download the project files. Run python main_ui.py to start the combat sim.
Note: this project requires Python 3 and tkInter to run. Mac installations of Python 3 may not automatically have tkInter installed.

Press Enter to switch between adding units and the battle screen. Press R on the unit input screen to run headless mode. On the battle screen, press Space twice to start the simulation (use Space to pause/resume afterwords). You can also use the left/right arrow keys to change the simulation speed.

This is a list of mechanics used in the simulation:
Combat
Feature Ideas
Units

Developing UI with tkInter was difficult for a number of reasons; documentation on tkInter is sparse and often outdated. tkInter's sticky property (essentially the tkInter version of flex-grow in CSS) must be manually set on all UI elements that should resize as the application window changes size, and getting even the simple UI it has now to work with that was a nightmare. tkInter also doesn't have a standard number input out of the box, so you have to use validation with a string input box, which is really weird.

tkInter is very similar to Swing for Java GUIs, and was an interesting change from working with HTML - it's much easier to rapidly prototype UI with HTML/CSS, and although both use hierarchies to organize UI, the syntax of HTML makes it much easier to understand (which made debugging UI elements' sticky property difficult in tkInter).

I was surprised to find tkInter wasn't installed on standard Python 3 installations for the Mac user who demoed the application, but the program was designed primarily for Windows/Linux, so I don't consider that a failure for the project.

If I developed Python UIs in the future, I would use a different library like PyQt - tkInter coming with the standard installation is great, but the documentation is really lacking to the point where it'd be more worth just installing extra third-party libraries that are easier to use.