How can I get the opposite value of a Bool in Swift?

Question

My specific case is I am trying to toggle the nav bar hidden and showing.

    let navHidden = !self.navigationController?.navigationBarHidden
    self.naviga         


        

Answer 1

navHidden! is to make sure this is not optional. !navHidden is the correct way to do that.

From Apple's book.

Trying to use ! to access a non-existent optional value triggers a runtime error. Always make sure that an optional contains a non-nil value before using ! to force-unwrap its value.