I'm trying to program an application for learning vocabulary words. I'd like to be able to easily add single words from the Books application using the "Share ..." affordance. However the share extension (and action extension) don't show up in that surface, even with TRUEPREDICATE as the NSExtensionActivationRule.
Facebook shows up as a valid target though, so it seems like there's some way to do it. Is Facebook manually approved by Apple/is there any way that I can make this, even if it's not approvable by the App Store?
There's no supported way for you to get text from a book in Apple Books with the APIs currently available. If you'd like us to consider adding the necessary functionality, please file an enhancement request using Feedback Assistant. Once you file the request, please post the FB number here. If you're not familiar with how to file enhancement requests, take a look at Bug Reporting: How and Why?
There are a predefined set of apps allowed to receive data from Books. This is not achievable with our presently shipped configurations.
Rico
WWDR - DTS - Software Engineer