Apps that accept input from the Activity popup automatically register themselves with the dialog. There isn’t anything from the Corona side that you need to do (or can do). In fact I did a test. I installed WeChat and it works. However you have to do some setup on your iDevice. First, I setup a simple button/tap handler in my Corona built app:
Then tap the button and the activity dialog shows:
Then scroll to the right and hit the “More” button
Scroll down until you find WeChat and turn it on
Press done and WeChat has been added to your iOS Activity dialog. At this point, nothing is Corona specific.
Then code wise I just copy/pasted the example code for “Combined Items”, changes the name of the image filename. I did get a weird error from WeChat if I just tried to send a string. But some combination of Image and URL has to be sent with it, but I didn’t dig in to find out specifically which one.
Rob