it worked for my HP : take your inks out, turn off the printer (disconnect it from the power while the cardriges are out) clean the gold pins with some cloth or Isopropyl alcohol or so turn on the printer (it will say no ink) than just put the ink back in and try to print i fixed my HP 10x like this

what's your phone? and which Android are you running? did you drop the phone? it is possible that the camera disconnected itself when you drop the phone (if you did) but just try a reboot/safe mode and look whether it helps

well if reboot doesn't fix the issue than i guess you need to look inside and maybe replace the keys, but cleaning them inside is the first thing to do Oil from the hands and dirt gets inside and the buttons don't work anymore... same with gamepads and remotes

Well, if the Phone is new than send it back and you'll get fixed one If the Phone isn't new you can try to factory reset your phone, however something like this tells me that the battery may be faulty...