AdMob 横幅：致命错误：在展开可选值时意外发现 nil

Question

我有一个加载 URL 的 WKWebView，并且 AdMob 横幅视图显示在 WKWebView 的底部。但是，当我运行应用程序时，我不断收到错误消息：“致命错误：在展开可选值时意外发现 nil”。

这是我的代码：

@IBOutlet var bannerView: GADBannerView!

var webView : WKWebView!
var progressView : UIProgressView!

override func loadView() {
    webView = WKWebView()
    webView.navigationDelegate = self
    view = webView
}

override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
    if keyPath == "estimatedProgress" {
        progressView.progress = Float(webView.estimatedProgress)
    }
}

override func viewDidLoad() {
    super.viewDidLoad()

    let url = URL(string: "https://www.facebook.com")!
    webView.load(URLRequest(url: url))
    webView.allowsBackForwardNavigationGestures = true

    navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Open", style: .plain, target: self, action: #selector(openTapped))
    progressView = UIProgressView(progressViewStyle: .default)
    progressView.sizeToFit()
    let progressButton = UIBarButtonItem(customView: progressView)
    let spacer = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
    let refresh = UIBarButtonItem(barButtonSystemItem: .refresh, target: webView, action: #selector(webView.reload))

    toolbarItems = [progressButton, spacer, refresh]
    navigationController?.isToolbarHidden = false

    webView.addObserver(self, forKeyPath: #keyPath(WKWebView.estimatedProgress), options: .new, context: nil)

    loadAd()

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

func loadAd() {
    bannerView.isHidden = true   //error happens at this line

    bannerView.delegate = self

    bannerView.adUnitID = "ca-app-pub-..." //id is here
    bannerView.adSize = kGADAdSizeSmartBannerPortrait
    bannerView.rootViewController = self
    bannerView.load(GADRequest())
}

func openTapped() {
    let ac = UIAlertController(title: "Open page…", message: nil, preferredStyle: .actionSheet)
    ac.addAction(UIAlertAction(title: "apple.com", style: .default, handler: openPage))
    ac.addAction(UIAlertAction(title: "hackingwithswift.com", style: .default, handler: openPage))
    ac.addAction(UIAlertAction(title: "Cancel", style: .cancel))
    present(ac, animated: true)

    ac.popoverPresentationController?.barButtonItem = self.navigationItem.rightBarButtonItem
}

func openPage(action: UIAlertAction) {
    let url = URL(string: "https://" + action.title!)!
    webView.load(URLRequest(url: url))
}

func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    title = webView.title
}

func adViewDidReceiveAd(_ bannerView: GADBannerView) {
    bannerView.isHidden = false
}

func adView(_ bannerView: GADBannerView, didFailToReceiveAdWithError error: GADRequestError) {
    bannerView.isHidden = true
}

我无法弄清楚导致此错误的原因 - 控制台没有提供有关它所指的可选值的详细信息。在我尝试添加横幅广告之前，WKWebView 运行良好，所以我认为这与它有关。

更新：这显示在控制台中： self.bannerView 的打印说明： 表达式产生错误：错误：/var/folders/yn/kndnb8ws7bz1r0rc11fnpndw0000gn/T/./lldb/485/expr3.swift:1:99：错误：使用未声明的类型“GoogleMobileAds” Swift._DebuggerSupport.stringForPrintObject(Swift.UnsafePointer>(bitPattern: 0x11b5272a0)!.pointee) ^~~~~~~~~~~~~~~~~~

Answer 1

我遇到了类似的问题，并且能够解决它。这可能对某人有帮助...

我的问题是我没有设置 IBOutlet 变量，而是设置了

var bannerView: GADBannerView!

但我需要使用 IBOutlet 将我的故事板中的视图附加到我的 ViewController

@IBOutlet var bannerView: GADBannerView!

我会确保它的链接正确。

除此之外，我还删除了以编程方式将bannerView 添加到故事板的代码。如果您混合故事板并以编程方式添加它，我认为这也会导致一些问题

Answer 2

很可能您没有连接“bannerView”IBOutlet 变量和相关的故事板视图。