Theme changing as you describe is not possible. State changes (based on a radio button indicator) can be done via conditional formatting, but you still need to create objects to apply the formatting to.
There are things via conditional formatting that get you close, but you would need to try and recreate the themes with conditionally formatted objects.
Theoretically, you might be able to use a combination of the custom 12 theme hack:
and a script trigger to export/overwrite a local CSS file in the custom theme folder. I could see this as seriously borking your file though or just plain not working, or crashing filemaker all together. I'd highly recommend backups before trying.
Thank you Mike
I think that the better way to simulate what you want is to have two layouts, the first with a pre-loaded theme "wave", the last with pre-loaded theme "Retro"; the radio button set simply fires a script to change them.
Daniele speaks the truth, this is actually better anyways than switching themes, as the text size differences between themes would skew how your layout looks when switched.
Unfortunately, this also doubles the number of layouts in your file, so hopefully you don't have a lot to make.
This was one of my initial ideas but as you see its a double edged sword hahahaha. The DB is in its infant stages so I will mostly wait until a more finalized version is in place before I double my work. In reality it shouldn't be too difficult to keep up with, I can just make changes to one layout (so far I have about 12 layouts that would need a theme "partner") and duplicate, then change the theme to minimize work. Thank you both so much for all of your help
or separate them out by folder and just know that you need to make changes/additions in the same place in each layout group folder.