Doors and Windows - hanging a door on a crooked wall

I'm trying to hang a bifold door in the hallway to my room. I live in a small condo so I don't want a regular door. The space is one inch wider at the top than it is at the bottom so a gap occurs when I put the door in the space. How can I fill in the gap?

I'm assuming that you are hanging the door directly on the wall without a finished opening ( jamb, trim, etc.)? You will have to install your top track and bottom pivot where they have to go and will have a space at the top side. No way around it unless you build a rough opening with 2x4's and install a finished jamb that is plumb and level. This way you can lose your 1" in the rough work. You will however have to get a smaller door.

I am building a rough frame with 2x4's on the wall but the frame will be crooked because the wall is crooked but if i make the frame straight then there is a big gap on the top between the frame and one side of the wall which is the crooked wall.

I would frame the opening square then put moulding around the door frame to cover the gap.