Migrating from UIWebView to WKWebView

Question

I'm migrating from UIWebView to WKWebView, how can I rewrite these function for WKWebView?

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

and

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)
}

Sounds like you should take a look at the navigationDelegate of the WKWebView. — luk2302
– luk2302, Commented May 29, 2016 at 12:46
Similar issue - may help you - stackoverflow.com/questions/46793618/ios-wkwebview-vs-uiwebview — Krunal
– Krunal, Commented Oct 18, 2017 at 11:43

clarkttfu · Accepted Answer · 2021-01-17 13:58:26Z

256

UIWebView => WKWebView Equivalent

UIWebViewDelegate => WKNavigationDelegate

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

About shouldStartLoadWithRequest you can write:

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)
}

And for the 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)
}

edited Jan 17, 2021 at 13:58

clarkttfu

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answered May 29, 2016 at 18:28

Alessandro Ornano

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5 Comments

Michal Cichon Over a year ago

webViewDidFinishLoad and didFinishNavigation are not exactly the same. The didFinishNavigation method is called before the page is fully loaded.

Gargo Over a year ago

documentation says that this method is for osx only. The question was for iOS

Alessandro Ornano Over a year ago

@Gargo Take a look to both the descriptions: webViewDidFinishLoad , didFinishNavigation , as you see is available also for iOS 8.0+

Siva Over a year ago

stackoverflow.com/questions/46171410/… - anyone help me this issue @AlessandroOrnano

Mike Keskinov Over a year ago

Just short note that these methods are declared in WKNavigationDelegate (notWKUIDelegate).

Pranav Kasetti · Accepted Answer · 2021-09-05 13:11:13Z

43

Here is the Objective-C methods for the migration:

shouldStartLoadWithRequest -> decidePolicyForNavigationAction

Remember to call the 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 {
}

edited Sep 5, 2021 at 13:11

Pranav Kasetti

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answered Apr 10, 2018 at 14:49

ajw

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1 Comment

CupawnTae Over a year ago

should that be WKNavigationTypeLinkActivated rather than UIWebViewNavigationTypeLinkClicked?

AamirR · Accepted Answer · 2023-02-26 17:59:44Z

16

Migrating UIWebView to WKWebView, Swift 4:

Equivalent of 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.open(url)    // Open in Safari
    }
}

Equivalent of webViewDidStartLoad:

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

Equivalent of 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/"))
    }
}

Equivalent of webViewDidFinishLoad:

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

edited Feb 26, 2023 at 17:59

answered Feb 11, 2018 at 18:30

AamirR

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1 Comment

Joseph Over a year ago

Small update: in shouldStartLoadWithRequest function, openURL(url) has been deprecated. It is not just open(url)

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