I accidentally uninstalled one of my Factory App. What would I do to restore it? My phone was in my pocket for the whole afternoon until one of my friends borrowed it then gave it back again then asked why did I uninstalled my Camera though I always use it. I tried to open my Camera but it always says "App not installed" I tried to find it in Google play to see if Lenovo Cameras were there but they weren't. I also opened my gallery and the same thing happened, to see... My Phone Camera and Gallery are connected. What should I do? Searched online but nothing really helps...
I'd say your friend is making fun with you. If it's a system app (and there's usually a camera pre-installed that way), it cannot be uninstalled without root access (so you cannot have "accidentally uninstalled" those apps). He most likely disabled camera and gallery.


Go to Settings → Apps
Select the "All" tab (to list pre-installed apps as well)
Scroll the list to find your camera app. Check whether it is marked "disabled".

if so: tap that entry, hit the "Enable" button, done.

Repeat previous step for your gallery app