You can simply set the Navigation Bar Color in XCode using one line of code.

I have setup a XCode project with a simple navigation controller as the root view controller of the default view. It looks like:

To set the navigation bar color simply add the following line of code in viewDidLoad()

    override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationController?.navigationBar.barTintColor = UIColor.redColor()
    }

If you run the app you will now see the Navigation Bar has a red color to it:

To set it to a custom color use the RGB code as follows, replacing the 100 with your relevant RGB codes.

    override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationController?.navigationBar.barTintColor = UIColor(red: 100/255, green: 100/255, blue: 100/255, alpha: 1)
    }

The above line of code sets it to gray using the RGB colors as follows: