How do I keep my kitty in?

My little 1 year old cat tries to leave through the door when I open it to come or go. This has not proved to be a huge problem (because we live in an apartment building so he only got as far as the hall) but now we are moving to a condo whose door leads right to the outside. I am trying to brainstorm a way to make sure he stays in. He is black and the street I am moving to is dark and I often leave at night for work. There are also a lot of wild animals around. Do u have any suggestions?

This may sound rather odd - but -
   
You could build a small vestibule inside your condo at the front door. It can be a simple 3-sided box, about 4 ft x 4 ft on the floor, & 7-8 feet tall, enough room to stand in.
   
This kind of vestibule is extremely common in older homes of all kinds & on detached homes looks like a tiny enclosed porch.
   
The vestibule cube can be attached to the wall studs on either side of the door leading outside with some heavy-duty brackets. Hang an inexpensive screen door (from the home store) on the side opposite the outside door. Make sure the inside door latches.
   
You can design it to look good in your condo, paint the door to complement the room, that kind of thing. It can be temporary or permanent. You can have it custom-made, or come up with a cheaper solution.
   
This way, you can open the interior door, make sure the cat is on the living room side of it when you're inside the vestibule. This way, when you open the outer door to leave or come in, the cat cannot get to the open door. So when you come into the vestibule when you come home, you close the outer door before you open the inner door.
   
I think this could work, & you could work it into the room without too much trouble.