func loadAds() {
    bannerView = ADBannerView(adType: ADAdType.Banner)
    bannerView.hidden = true
    bannerView.delegate = self
    self.view.addSubview(bannerView)
}

override func viewDidLayoutSubviews() {
    self.layoutAnimated(UIView.areAnimationsEnabled())
}

func layoutAnimated(animated: Bool) {
    var contentFrame = self.view.bounds

    var sizeForBanner = bannerView.sizeThatFits(contentFrame.size)

    var bannerFrame = bannerView.frame
    if self.bannerView.bannerLoaded {

        contentFrame.size.height -= sizeForBanner.height
        bannerFrame.origin.y = contentFrame.size.height
        bannerFrame.size.height = sizeForBanner.height
        bannerFrame.size.width = sizeForBanner.width

        let verticalBottomConstraint = self.bottomConstraint
        verticalBottomConstraint.constant = sizeForBanner.height
        self.view.layoutSubviews()
        bannerView.hidden = false
    } else {
        bannerFrame.origin.y = contentFrame.size.height
        bannerView.hidden = true
        let verticalBottomConstraint = self.bottomConstraint
        verticalBottomConstraint.constant = 0
    }
    UIView.animateWithDuration(animated ? 0.25 : 0.0, animations: {
        self.contentView.layoutIfNeeded()
        self.bannerView.frame = bannerFrame
    })
}

func bannerViewDidLoadAd(banner: ADBannerView!) {
    self.layoutAnimated(true)
}

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