Important Note: because of the way Hangouts is built, you'll have to have the Android Wear app installed on your device for this to work for Hangouts.
For other Android messaging apps it should work even without the Android Wear app installed.
STEP 1 - INTERCEPT NOTIFICATION WITH REPLY ACTION
Some messaging apps are not supported. There's nothing AutoNotification can do to make it work if the apps don't create their notifications with reply information. You may want to contact the app's developers so that they add this information to their notifications.
- Create a Tasker profile with the AutoNotification Intercept condition
- Check the Has Reply Action option
- In the Apps option, select any app you want that you receive messages in like Hangouts, Facebook, Whatsapp, etc.
STEP 2 - SHOW FLASH
Messaging app's notifications usually have the contact name in the notification title. That's why we're using that here
- Add a flash action with the text Replying to %antitle
STEP 3 - REPLY TO CONTACT
AutoNotification has since been updated. The Reply ID option mentioned below is now under Advanced.
- Add an AutoNotification Reply action
- Make sure that the Reply ID is filled with %anreplyaction
- Set the Reply Text to whatever you want to reply
STEP 4 - SET COOLDOWN IF NEEDED
Some apps like Hangouts have a weird behavior where the notification is re-created after it's replied to. Because of that the profile will trigger twice if we let it. Set the cooldown time on the profile to 5 seconds to prevent that.
- Long-press the profile and choose Settings
- Set the Cooldown Time to 5 seconds
Now if someone sends you a message this should happen: