WKWebView 未打开自定义 URL 方案（js 在新窗口中打开自定义方案链接）

Question

我的应用程序中有一个WKWebView。我不使用UIWebView，因为出于某种奇怪的原因，它无法正确打开包含大量 JS 代码的网页。

当我点击带有自定义 url 方案 "scm://"的链接时，它什么都不做......

我的代码：

- (void)viewDidLoad {
    // ...

    WKWebViewConfiguration *configuration = [WKWebViewConfiguration new];
    if ([configuration respondsToSelector:@selector(setDataDetectorTypes:)])
        [configuration setDataDetectorTypes:WKDataDetectorTypeLink];

    myWebView = [[WKWebView alloc] initWithFrame:webFrame configuration:configuration];
    myWebView.navigationDelegate = self;

    [self.view addSubview:myWebView];
}

#pragma mark - WKNavigationDelegate

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler
{
    NSURL *requestURL = navigationAction.request.URL;
    UIApplication *app = [UIApplication sharedApplication];
    if ([requestURL.scheme.lowercaseString isEqualToString:@"scm"] && [app canOpenURL:requestURL]) {
        [app openURL:requestURL];
        decisionHandler(WKNavigationActionPolicyCancel);
    }
    else
        decisionHandler(WKNavigationActionPolicyAllow);
}

- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation
{
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}

- (void)webView:(WKWebView *)webView didFailNavigation:(WKNavigation *)navigation withError:(NSError *)error
{
    [self handleError:error];
}

- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(WKNavigation *)navigation withError:(NSError *)error
{
    [self handleError:error];
}

#pragma mark - Handle web view errors.

- (void)handleError:(NSError *)error
{
    UIApplication *app = [UIApplication sharedApplication];
    app.networkActivityIndicatorVisible = NO;

    NSURL *failedUrl = error.userInfo[NSURLErrorFailingURLErrorKey];

    if ([failedUrl.scheme.lowercaseString isEqualToString:@"scm"]) {
        [app openURL:failedUrl];
    }
}

当我单击自定义 url 时，从不调用 handleError()，也不会调用 decisionPolicyForNavigationAction()。

Answer 1

好的，想通了...碰巧链接在新窗口中打开，因此添加下一个代码以及设置 UIDelegate 使其工作

    // Somewhere in viewDidLoad()...
    myWebView.UIDelegate = self;
}

- (WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures
{
    NSLog(@"createWebViewWithConfiguration %@ %@", navigationAction, windowFeatures);
    if (!navigationAction.targetFrame.isMainFrame) {
        [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
        [(WKWebView *)_webView loadRequest:navigationAction.request];
    }
    return nil;
}

Answer 2

-(void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler{

    NSURLRequest *request = navigationAction.request;
    if(![request.URL.absoluteString hasPrefix:@"http://"] && ![request.URL.absoluteString hasPrefix:@"https://"]) {
        if([[UIApplication sharedApplication] canOpenURL:request.URL]) {
            //urlscheme, tel, mailto, etc.
            [[UIApplication sharedApplication] openURL:request.URL];
            decisionHandler(WKNavigationActionPolicyCancel);
            return;
        }
    }
    decisionHandler(WKNavigationActionPolicyAllow);
}

注意：此答案仅针对 urlscheme，但可能会导致其他问题。感谢您的反馈意见！

Answer 3

在雨燕5.1在iOS 13.1.3（变化以下作品@ hstdt的回答）为WKWebView处理最低限度以下（测试）模式：sms:，tel:，和mailto:。

将以下内容添加到您设置WKWebView.

// assign the delegate
webView.navigationDelegate = self

然后，在类中的某处添加以下函数。

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

    // if the request is a non-http(s) schema, then have the UIApplication handle
    // opening the request
    if let url = navigationAction.request.url,
        !url.absoluteString.hasPrefix("http://"),
        !url.absoluteString.hasPrefix("https://"),
        UIApplication.shared.canOpenURL(url) {

        // have UIApplication handle the url (sms:, tel:, mailto:, ...)
        UIApplication.shared.open(url, options: [:], completionHandler: nil)

        // cancel the request (handled by UIApplication)
        decisionHandler(.cancel)
    }
    else {
        // allow the request
        decisionHandler(.allow)
    }
}

解释：

• WKWebView 似乎无法处理非 http(s) url 模式。
• 上面的代码在 WKWebView 有机会渲染/加载它以检查不同的模式之前捕获请求。
• 我们检查非 http(s) 模式并让 UIApplication 处理它。

注意：如果您发现其他模式在使用此解决方案时有效或无效，请发表评论。

同样，这个解决方案是从@hstdt 的答案中获取和修改的。

Answer 4

Swift 5 的解决方案： 以下是 mattblessed 对 WKWebView 的答案的变体，它适用于所有应用程序 URL 方案，而不仅仅是系统 URL 方案，如“sms:”、“tel:”和“mailto:”

该解决方案无需通过LSApplicationQueriesSchemes. （从 iOS 10 开始这是必需的 - 有关详细信息，请参阅这篇文章：canOpenURL 在 ios 10 中不起作用）

将以下实现添加WKNavigationDelegate到您的类中：

func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
    if let requestUrl = navigationAction.request.url, requestUrl.isCustomUrlScheme() {
        decisionHandler(.cancel)

        // try to open URLs like e.g. "whatsapp://"
        UIApplication.shared.open(requestUrl, options: [:]) { success in
            if !success {
                //TODO 
                // add your code for handling URLs that can't be opened here - 
                // maybe show an error alert
            }
        }
    } else {
        // allow the request
        decisionHandler(.allow)
    }
}

将以下扩展添加URL到您的类中：

extension URL {

    func isCustomUrlScheme() -> Bool {
        let webUrlPrefixes = ["http://", "https://", "about:"]

        let urlStringLowerCase = self.absoluteString.lowercased()
        for webUrlPrefix in webUrlPrefixes {
            if urlStringLowerCase.hasPrefix(webUrlPrefix) {
            return false
        }

        return urlStringLowerCase.contains(":")
    }
}