Landlord randomly entering the apt, doing small projects,...

[Nick Drago]

Hi, I know that this might not be the best forum to write to but I have found many solutions to my problems here and I am really grateful for everyones' help! Here is my issue:

I am currently renting an apartment in Omaha, Nebraska and after 10 month of no issues with my landlord he decided that one day he would just come into the apartment and show the potential new tenants the apartment when my family was staying with me without a notice. A week later he decided he wants to put in ceiling lights in the living room and bedroom, this time with a 2 day warning ( first day everything was dirty and lose wires and i told him i didn't want them) then 3 day after that decided he wanted to take down the wallpaper in the bedroom with a one days notice. So i decided I will give him 3 days to finish anything he needed at the apartment and i will stay with my friend. I came back after 3 days and half a wall had no wallpaper and in the middle of the other wall there was just a huge chuck torn. I fixed the hanging wallpaper...but 

what can i do stop him from randomly coming to the apartment when he wants and do repairs if i don't need them! Is there a law for tenants that prohibits that and what will it take for me to get out of the contract if i wanted to. 

I feel like i don't have any privacy at all! 

I would really appriciate any help!

Thank you