My dog cries and pees himself if we try to take him outside the apartment?

I have a dog who I found on the streets also. When I first got her she refused to go out even when I tugged on her leash. I would open the door and even try to entice her with treats and she refused to walk through the door. It took about a month of me opening the door, picking her up and placing her on the other side of the doorway for her to understand that it was ok for her to go through the doorway. 3 years later she doesn't hesitate one bit and loves going outside. I think as long as you stay persistent with your dog you can get him to go outside without a problem but it will take some time and effort on your part.