I use intent and Action.SEND for sharing my custom message on social networks like WhatsApp , twitter, Facebook and GMail. Everything is ok on Gmail and other applications e
As per the Facebook's Platform Policies, you cannot pre-fill the share dialog using
Intent.EXTRA_TEXT
. It is usually thought to be a bug, but as per a Bug Report filed here and also, here, Facebook clearly mentions that this is not the case (it's not a bug).
You can read more about their Platform Policies specifically, Platform Policy IV.2
Quote from Platform Policy IV.2:
You must not pre-fill any of the fields associated with the following products, unless the user manually generated the content earlier in the workflow: Stream stories (user_message parameter for Facebook.streamPublish and FB.Connect.streamPublish, and message parameter for stream.publish), Photos (caption), Videos (description), Notes (title and content), Links (comment), and Jabber/XMPP.
These fields are intended for users to express themselves. Pre-filling these fields erodes the authenticity of the user voice.
The only way you can share stories from your App is by integrating the Facebook SDK, which as per your post, you are already able to successfully. That is the only option available (unfortunately).