ios:how to add google ads on back button of navigation item in swift?

Question

 let backButton = UIBarButtonItem(
        title: "",
        style: UIBarButtonItemStyle.Plain,
        target: nil,
        action: nil
    );
    self.navigationController!.navigationBar.tintColor = UIColor.whiteColor()
    self.navigationController!.navigationBar.topItem!.backBarButtonItem = backButton;

i have use above code and i want to add google Interstitial ads in back button of navigation item. my requirement is when i press back from second viewcontroller ads. should would be come and when i close ads. first view controller should open.

thanks

Answer 1

i solved my problem by adding this below code in secondViewController. and its work perfectly.

 override func viewWillDisappear(animated: Bool) {
    if (interstitial.isReady && showAd) {
        showAd = false
        print("iterstitalMain is ready")
        interstitial.presentFromRootViewController(parentViewController!)
        self.createAndLoadInterstitial()
    }
    else{
    }
}