I have spent a good while trying to understand just what the Watchmaker dev did to protect his files, and it doesn't look like i'm getting anywhere with that. So here's an update that at least handles the files without crashing, still has most functionality even with the protected Watchmaker files, but you can't edit the XML or the images. It also improves a few other things throughout the app, so it's recommended anyone using this program updates.
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If anyone knows with certainty what the Watchmaker dev is doing to protect the XML I would love to hear from you. I decompiled the watchmaker apk and he seems to be using the standard Android Base64 Util class, but nothing I've tried is getting me a clear decoded XML file on my end with Visual Studio (i've also tested with various online decoding tools to make sure it wasn't a Studio limitation), so there's some further obfuscation going on besides the simple encoding to Base64 it looks like at first blush.
As far as the images, he's encrypting both the .jpg (to .pjpg) and the .png (to .ppng) images, and without knowing more information, decrypting them can be tough or impossible. It's not the simple Base64 protection that Facer uses. The encrypted headers for all the .pjpg images I've looked at is the same, so whatever encryption he's using, the encrypted values don't change from file to file, that's for sure. If you can shed light on this, that'd be great too.
Otherwise, we can work with the protected files but won't be able to edit them. I personally don't care about it, but I tried for you guys. Sucks I couldn't get beyond what I did.