How can I use somebody else's app extension?

Question

There seem a lot of activities and infos on building application extensions so that other apps may use them. But I don't see any concrete info on how to set up my app in order to use others' extensions. Not here nor Apple's doc. What am I missing?

Answer 1

What you're missing is UIActivityViewController. You create one with the data that you want to make available to app extensions. When you display it, iOS includes whatever app extensions are currently installed that support the data you've provided. So if you include a photo, any extension that can handle photos will be listed.

UIActivityViewController is commonly displayed when the user taps a "share" button.

You don't get to call other app's extensions directly-- you provide the data, and iOS allows the user to choose from the extensions that support the data.