I have zero experience with Samsung or Android 4.2, but I just stumbled across this post suggesting camera from a secured lockscreen may be possible:
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forum.xda-developers.com ··· 45911508So, maybe a little more research into what dib22 mentioned will pay off. Also, maybe it requires a stock camera app as opposed to whatever Samsung builds in.
Edit- I started to add that some custom ROMs may offer the functionality you desire. For example, some Cyanogenmod ROMs offer an option to long-press a button to toggle the flashlight, even with a secured lockscreen. Then, I remembered the Xposed framework & modules:
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forum.xda-developers.com ··· =1574401Here's an Xposed module that purports to do what you want, at least for the camera:
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forum.xda-developers.com ··· =2363189Worst case, a combination of custom ROM & Xposed should be able to do it all if you're willing to put in the work.