Displaying an Activity on the Android lock screen

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http://stackoverflow.com – I'm trying to figure out how exactly (if it's possible) to replicate the way the camera app works on the Jelly Bean lock screen. From the lock screen, I can swipe left and the camera app displays, if I swipe right, I have the ability to add widgets. Would it be possible to provide an activity in such a manner it can be added to the lock screen, or is this only available for the default camera app? (HowTos)