从 UIWebView 迁移到 WKWebView答案

【问题标题】：Migrating from UIWebView to WKWebView从 UIWebView 迁移到 WKWebView
【发布时间】：2016-09-27 08:35:57
【问题描述】：

在我的应用程序中，我正在从 UIWebView 迁移到 WKWebView ，如何为 WKWebView 重写这些函数？

    func webViewDidStartLoad(webView: UIWebView){}
    func webViewDidFinishLoad(webView: UIWebView){}

和

    func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
        print("webview asking for permission to start loading")
        if navigationType == .LinkActivated && !(request.URL?.absoluteString.hasPrefix("http://www.myWebSite.com/exemlpe"))!{
            UIApplication.sharedApplication().openURL(request.URL!)
            print(request.URL?.absoluteString)
            return false
        }
        print(request.URL?.absoluteString)
        lastUrl = (request.URL?.absoluteString)!

        return true
    }


    func webView(webView: UIWebView, didFailLoadWithError error: NSError?) {
        print("webview did fail load with error: \(error)")
        let testHTML = NSBundle.mainBundle().pathForResource("back-error-bottom", ofType: "jpg")
        let baseUrl = NSURL(fileURLWithPath: testHTML!)

        let htmlString:String! = "myErrorinHTML"
        self.webView.loadHTMLString(htmlString, baseURL: baseUrl)
    }

【问题讨论】：

听起来你应该看看navigationDelegate 的WKWebView。
类似问题-可能对您有所帮助-stackoverflow.com/questions/46793618/ios-wkwebview-vs-uiwebview

标签： ios swift uiwebview wkwebview

【解决方案1】：

这是迁移的 Objective-C 方法：

shouldStartLoadWithRequest -> 决定PolicyForNavigationAction

记得拨打decisionHandler:

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
       if (navigationAction.navigationType == WKNavigationTypeLinkActivated) {

       }
       NSString *url = [navigationAction.request.URL query];
                
       decisionHandler(WKNavigationActionPolicyAllow);
}

webViewDidStartLoad -> didStartProvisionalNavigation

- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation *)navigation {
}

webViewDidFinishLoad -> didFinishNavigation

- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation {
}

didFailLoadWithError -> didFailNavigation

- (void)webView:(WKWebView *)webView didFailNavigation:(WKNavigation *)navigation withError:(NSError *)error {
}

【讨论】：

应该是WKNavigationTypeLinkActivated 而不是UIWebViewNavigationTypeLinkClicked？

【解决方案2】：

UIWebView => WKWebView 等效

UIWebViewDelegate => WKNavigationDelegate

delegate => navigationDelegate
didFailLoadWithError => didFailNavigation
webViewDidFinishLoad => didFinishNavigation
webViewDidStartLoad => didStartProvisionalNavigation
shouldStartLoadWithRequest => decidePolicyForNavigationAction

关于shouldStartLoadWithRequest可以写：

func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
    print("webView:\(webView) decidePolicyForNavigationAction:\(navigationAction) decisionHandler:\(decisionHandler)")
    
    switch navigationAction.navigationType {
        case .linkActivated:
        if navigationAction.targetFrame == nil {
            self.webView?.loadRequest(navigationAction.request)
        }
        if let url = navigationAction.request.url, !url.absoluteString.hasPrefix("http://www.myWebSite.com/example") {
            UIApplication.shared.open(url)
            print(url.absoluteString)
            decisionHandler(.cancel)
        return
        }
        default:
            break
    }
    
    if let url = navigationAction.request.url {
        print(url.absoluteString)
    }
    decisionHandler(.allow)
}

对于didFailLoadWithError：

func webView(_ webView: WKWebView, didFail navigation: WKNavigation!, withError error: Error) {
    print("webView:\(webView) didFailNavigation:\(navigation) withError:\(error)")
    let testHTML = Bundle.main.path(forResource: "back-error-bottom", ofType: "jpg")
    let baseUrl = URL(fileURLWithPath: testHTML!)

    let htmlString = "myErrorInHTML"
    self.webView.loadHTMLString(htmlString, baseURL: baseUrl)
}

【讨论】：

webViewDidFinishLoad 和 didFinishNavigation 并不完全相同。在页面完全加载之前调用 didFinishNavigation 方法。
文档说这种方法仅适用于 osx。问题是针对 iOS 的
@Gargo 看看这两个描述：webViewDidFinishLoad，didFinishNavigation，正如你所见，iOS 8.0+ 也可以使用
stackoverflow.com/questions/46171410/… - 任何人都可以帮我解决这个问题@AlessandroOrnano
请注意，这些方法是在WKNavigationDelegate（不是WKUIDelegate）中声明的。

【解决方案3】：

将 UIWebView 迁移到 WKWebView，Swift 4：

相当于shouldStartLoadWithRequest：

func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
    var action: WKNavigationActionPolicy?

    defer {
        decisionHandler(action ?? .allow)
    }

    guard let url = navigationAction.request.url else { return }

    print(url)

    if navigationAction.navigationType == .linkActivated, url.absoluteString.hasPrefix("http://www.example.com/open-in-safari") {
        action = .cancel                  // Stop in WebView
        UIApplication.shared.openURL(url) // Open in Safari
    }
}

等价于webViewDidStartLoad：

func webView(_ webView: WKWebView, didStartProvisionalNavigation navigation: WKNavigation!) {
    print(String(describing: webView.url))
}

等价于didFailLoadWithError：

func webView(_ webView: WKWebView, didFail navigation: WKNavigation!, withError error: Error) {
    let nserror = error as NSError
    if nserror.code != NSURLErrorCancelled {
        webView.loadHTMLString("404 - Page Not Found", baseURL: URL(string: "http://www.example.com/"))
    }
}

等价于webViewDidFinishLoad：

func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    print(String(describing: webView.url))
}

【讨论】：