I was searching about how to send an email from my app and I came across this topic:
how to send email from my android app
it solves the problem adding a type to his action send:
I think you aren't supposed to force any kind of behavior when broadcasting a share intent.
This sets the MIME type of your intent. I guess, at best, you would have to know which MIME type the app which you intend to use in order to share your content (ex. Facebook) answers, and assure that that app is the only app that will answer your intent.