I adopted a cat who had been a barn cat. She was mean, cranky, and didn't like having to stay inside all the time. She'd constantly try to get out when I was entering or exiting the apartment, and I had to be careful she didn't get onto the balcony, lest she take the two-story leap to try and run away.
It took time, but she gradually got used to being inside. She still would do her daily attempt to leave when I was coming in (I had to put my foot in the door and shake it before opening the door) or going out, and I couldn't take her on the balcony unless I was holding her, but the one time she *did* run out, I scolded her and she ran right back inside.
If I'd let her run loose, she might've lived a few years longer. Instead, she had over a decade with me. No worries about being hit by cars, mauled by another animal, stolen by someone, taken by the animal control truck, picking up distemper, no fleas, and no mysterious injuries that wind up killing her. (My first cat used to scrap with all the neighborhood cats, and one particularly unfortunate scratch abscessed into his skull and killed him.)
Keeping a cat indoors is much like not letting your kids have ice cream for dinner every night. Yeah, it makes them upset, but they'll be happier, healthier, and better off for it.
If you still want her to have some outside time, get her accustomed to a harness and leash. Some cats will never take to it, but some find it almost as exciting as a dog would!