Real quick post today, but all the solutions I found for this were surprisingly verbose. Here's how:
Calling iOS Methods From Unity
1. In your C# class:
2. In your UnityAppController.mm:
Calling Unity C# Methods from Xcode
1. In your UnityAppController.mm:
Keep in mind that this only works on actual devices (not in the Editor) and is processor intensive so keep usage to a minimum.
Boom! That's it.