从 WKWebView 调用时，无法使用 JavaScript 在移动 Safari 中打开链接答案

【问题标题】：Cannot use JavaScript to open links in mobile Safari when called from WKWebView从 WKWebView 调用时，无法使用 JavaScript 在移动 Safari 中打开链接
【发布时间】：2016-10-26 00:31:57
【问题描述】：

This post 和this post 解决了在移动端Safari 中使用JavaScript 打开WKWebView 链接的问题，但是由于某种原因，提供的解决方案不起作用。

下面的代码合并了不同解决方案的元素，但点击按钮后仍然无法打开链接。

事实上，webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) 和 userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) 甚至都不会被调用。

HTML：

<html>
    <style type="text/css">
        #button { width: 100px; height: 50px; background: red; }
    </style>

    <div id="button">CLICK TO GO</div>

    <script type="text/javascript">

    var button = document.getElementById("button");
    button.addEventListener("click", doTest);

    function doTest() {
        window.open("http://www.google.com", target="_blank");
        button.innerHTML = "HEY";
    }

    </script>
</html>

视图控制器：

class ViewController: UIViewController, WKScriptMessageHandler, WKNavigationDelegate, WKUIDelegate {

    var webView: WKWebView?
    let webViewContentController = WKUserContentController()

    override func viewDidLoad() {
        super.viewDidLoad()

        let config = WKWebViewConfiguration()
        config.userContentController = webViewContentController

        webView = WKWebView(frame: view.bounds, configuration: config)

        webView!.navigationDelegate = self
        webView!.uiDelegate = self  //must have this

        var fileURL = URL(fileURLWithPath: Bundle.main.path(forResource:"Mooncake.html", ofType: nil)!)
        webView!.loadFileURL(fileURL, allowingReadAccessTo: fileURL)

        view.addSubview(webView!)
    }

    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
    }

    // this handles target=_blank links by opening them in the same view
    func webView(webView: WKWebView!, createWebViewWithConfiguration configuration: WKWebViewConfiguration!, forNavigationAction navigationAction: WKNavigationAction!, windowFeatures: WKWindowFeatures!) -> WKWebView! {
        if navigationAction.targetFrame == nil {
            let url = navigationAction.request.url!
            let urlString = url.description.lowercased()

            if urlString.contains("http://") || urlString.contains("https://") || urlString.contains("mailto:") {
                UIApplication.shared.openURL(url)
            }
        }
        return nil
    }

    func webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void) {
        if navigationAction.targetFrame == nil {
            webView.load(navigationAction.request)
        }
    }
}

【问题讨论】：

标签： ios swift safari wkwebview wkwebviewconfiguration

【解决方案1】：

问题在于使用过时的函数定义，从 SO 答案中提取，用于

webView(webView: WKWebView!, createWebViewWithConfiguration configuration: WKWebViewConfiguration!, forNavigationAction navigationAction: WKNavigationAction!, windowFeatures: WKWindowFeatures!) -> WKWebView!

和

webView(webView: WKWebView, decidePolicyForNavigationAction navigationAction: WKNavigationAction, decisionHandler: (WKNavigationActionPolicy) -> Void)

使用类文档定义的 Swift 3 函数定义解决了这个问题。

【讨论】：