How can I prevent the camera app from opening directly from my Nexus 4's lockscreen? It opens frequently and easily when the lock screen slides from right to left, even if the phone is locked with pattern. My phone is running Android 4.2.2.
I'm not aware of any native settings for this, but there is an app that was built to bridge the gap: Lockscreen Policy. When you first launch it, you'll need to hit the "Activate" button to give it device administration permission, then you simply toggle the camera to "Off":
One caveat to this app that the author notes on the Google Play page:
Does not work on TouchWiz Android 4.2.x firmware (such as Galaxy S4)
However, this does not apply in your case, since the N4 is not running TouchWiz.