Reloading a UINavigationItem - ios

Question

I want to load my view controller with one navItem.rightBarButtonItem and change it to another based on a set of circumstances. It seems as if I can only load it once, on viewDidLoad. Is there a method for updating a bar button item after you've changed the icon?
func viewDidLoad() {
var iconOne = UIImage(named: "button")
let buttonOne = UIBarButtonItem(image: iconOne, style: UIBarButtonItemStyle.Plain, target: self, action: "funcOne")
self.navItem.rightBarButtonItem = buttonOne
//perform async query, if a condition holds true then:
var iconTwo = UIImage(named: "buttonTwo")
let buttonTwo = UIBarButtonItem(image: iconTwo, style: UIBarButtonItemStyle.Plain, target: self, action: "funcTwo")
self.navItem.rightBarButtonItem = buttonTwo
}
Full code:
override func viewDidLoad() {
super.viewDidLoad()
// Sets custom nav bar view so we can add multiple bar buttons
navBar = UINavigationBar(frame: CGRectMake(0, 20, UIScreen.mainScreen().bounds.size.width, 44))
navBar.barTintColor = UIColor.blackColor() // Sets bar to black
navBar.translucent = false
self.view.addSubview(navBar)
navItem = UINavigationItem(title: "\(name)") // Sets title
navBar.titleTextAttributes = [ NSFontAttributeName: UIFont(name: "Helvetica Neue", size: 25)!, NSForegroundColorAttributeName: UIColor.whiteColor()]
// Set icons
var backIcon = UIImage(named: "backButton")
let backButton = UIBarButtonItem(image: backIcon, style: UIBarButtonItemStyle.Plain, target: self, action: "backButton")
navItem.leftBarButtonItem = backButton
var userQuery = PFQuery(className: "Followers")
userQuery.whereKey("following", equalTo: username)
userQuery.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in
if error == nil {
if let objects = objects {
for object in objects {
if let follower = object["follower"] as? String {
if follower == PFUser.currentUser()!.username! {
var followingIcon = UIImage(named: "followingButton")
let followingButton = UIBarButtonItem(image: followingIcon, style: UIBarButtonItemStyle.Plain, target: self, action: "unfollowUser")
self.navItem.rightBarButtonItem = followingButton
self.navItem.rightBarButtonItem?.tintColor = UIColor.orangeColor()
} else {
var followIcon = UIImage(named: "followButton")
let followButton = UIBarButtonItem(image: followIcon, style: UIBarButtonItemStyle.Plain, target: self, action: "followUser")
self.navItem.rightBarButtonItem = followButton
self.navItem.rightBarButtonItem?.tintColor = UIColor.darkGrayColor()
}
}
}
}
} else {
println(error)
}
})

Answer 1

I'm not sure if this is possible. So, I made my own custom view where each bar button item would be. I set my right bar button item at var rightButton = UIButton(frame: CGRectMake(UIScreen.mainScreen().bounds.width - 50, 25, 30, 30)), added an action, and added the subview to the view.