Can I have an app which allows user to adjust settings or properties, then when have a companion datafield which accesses those settings during activity?
I don't see any way to communicate data to a data field, but it seems that the intent system could work to shuttle settings between application and widget or vice-versa.
Good news. We just released a service that enables communication between apps. Shared settings can be built on top of this. You can learn more at https://dacrosse.com