iAd + FunFact Problem! Can't change view color, please help

//
//  ViewController.swift
//  NyttigViden
I cannot change my view color. I can do if when I remove the Ad, but how do I make it work with the Ad? Please help.



//
//  Created by Andreas Poulsen on 16/01/15.
//  Copyright (c) 2015 Andreas Lyngholm. All rights reserved.
//


import UIKit
import iAd

class ViewController: UIViewController, ADBannerViewDelegate{

    var bannerView:ADBannerView?

    @IBOutlet weak var funFactLabel: UILabel!
    @IBOutlet weak var funFactButton: UIButton!

    let factBook = FactBook()
    let colorWheel = ColorWheel()

    override func viewDidLoad() {
        super.viewDidLoad()
        self.canDisplayBannerAds = true
        self.bannerView?.delegate = self
        self.bannerView?.hidden = true
        funFactLabel.text = factBook.randomFact()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func showFunFact() {
        var randomColor = colorWheel.randomColor()
        funFactButton.tintColor = randomColor
        self.view.backgroundColor = randomColor
        funFactLabel.text = factBook.randomFact()
    }

    func bannerViewDidLoadAd(banner: ADBannerView!) {
        self.bannerView?.hidden = false
    }

    func bannerViewActionShouldBegin(banner: ADBannerView!, willLeaveApplication willLeave: Bool) -> Bool {
    return willLeave
    }

    func bannerView(banner: ADBannerView!, didFailToReceiveAdWithError error: NSError!) {
        self.bannerView?.hidden = true
    }
}