How to programmatically rotate the view by 180 degrees in my iPhone App?
Should be possible by using CGAffineTransform
Quote from this question, this should do the trick:
CGFloat radians = atan2f(yourView.transform.b, yourView.transform.a);
CGFloat degrees = radians * (180 / M_PI);
CGAffineTransform transform = CGAffineTransformMakeRotation((90 + degrees) * M_PI/180);
yourView.transform = transform;