It passes all the tests and I additionally added the option to use the calculator with the keyboard. Overall I am not as satisfied with my result, because I think that the code and overall structure of my app could be less complicated, but it does work as intended so I decided to go with it.
Also I really liked the design of the example project, which is why I decided to try and mimic it. Sometime in the future I am planning to go over this project again and that time take a different approach to solve this challenge and also use a different design that I like.
I ended up doing some refactoring of my code today, because I wanted to shorten my code. I created a new function that holds the calculator logic and replaced the switch statement with if/else statements so I could use logical operators. This let me shorten my code for about a third (went from 300 lines to about 200 lines). If anyone is interested in changes, you can compare them from below links: