不建议使用UIWebView和UIWebViewDelegate。你将不被允许将更新推送到Appstore。参考

使用WKWebView和WKNavigationDelegate

示例代码:

class YourClass: WKNavigationDelegate {

    override public func viewDidLoad() {
        super.viewDidLoad()
        let webView = WKWebView()
        webView.navigationDelegate = self
        self.view.addaddSubview(webView)
    }
    
    public func webView(_ webView: WKWebView,
                    didReceive challenge: URLAuthenticationChallenge,
                    completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        let cred = URLCredential(trust: challenge.protectionSpace.serverTrust!)
        completionHandler(.useCredential, cred)
    }

    public func webView(_ webView: WKWebView,
                    decidePolicyFor navigationAction: WKNavigationAction,
                    decisionHandler: @escaping (WKNavigationActionPolicy) -> Swift.Void) {
    
        self.webView.load(navigationAction.request)
        decisionHandler(.allow)
    }
}

不建议使用UIWebView和UIWebViewDelegate。你将不被允许将更新推送到Appstore。参考

使用WKWebView和WKNavigationDelegate

示例代码:

class YourClass: WKNavigationDelegate {

    override public func viewDidLoad() {
        super.viewDidLoad()
        let webView = WKWebView()
        webView.navigationDelegate = self
        self.view.addaddSubview(webView)
    }
    
    public func webView(_ webView: WKWebView,
                    didReceive challenge: URLAuthenticationChallenge,
                    completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        let cred = URLCredential(trust: challenge.protectionSpace.serverTrust!)
        completionHandler(.useCredential, cred)
    }

    public func webView(_ webView: WKWebView,
                    decidePolicyFor navigationAction: WKNavigationAction,
                    decisionHandler: @escaping (WKNavigationActionPolicy) -> Swift.Void) {
    
        self.webView.load(navigationAction.request)
        decisionHandler(.allow)
    }
}

公认的答案行不通。

如果你的页面通过Javascript加载url, navigationType将是UIWebViewNavigationTypeOther。不幸的是，这也包括后台页面加载，如分析。

要检测页面导航，需要比较[request URL]和[request mainDocumentURL]。

这个解决方案将在所有情况下工作:

- (BOOL)webView:(UIWebView *)view shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)type
{
    if ([[request URL] isEqual:[request mainDocumentURL]])
    {
        [[UIApplication sharedApplication] openURL:[request URL]];
        return NO;
    }
    else
    {       
        return YES;
    }
}

下面是Xamarin iOS版的drawnonward的答案。

class WebviewDelegate : UIWebViewDelegate {
    public override bool ShouldStartLoad (UIWebView webView, NSUrlRequest request, UIWebViewNavigationType navigationType) {
        if (navigationType == UIWebViewNavigationType.LinkClicked) {
            UIApplication.SharedApplication.OpenUrl (request.Url);
            return false;
        }
        return true;
    }
}

在Swift中，你可以使用以下代码:

extension YourViewController: UIWebViewDelegate {
    func webView(_ webView: UIWebView, shouldStartLoadWith request: URLRequest, navigationType: UIWebView.NavigationType) -> Bool {
        if let url = request.url, navigationType == UIWebView.NavigationType.linkClicked {
            UIApplication.shared.open(url, options: [:], completionHandler: nil)
            return false
        }
        return true
    }

}

确保检查了URL值和navigationType。

在我的例子中，我想确保web视图中的所有东西都能打开Safari，除了初始加载，所以我使用。

- (BOOL)webView:(UIWebView *)inWeb shouldStartLoadWithRequest:(NSURLRequest *)inRequest navigationType:(UIWebViewNavigationType)inType {
     if(inType != UIWebViewNavigationTypeOther) {
        [[UIApplication sharedApplication] openURL:[inRequest URL]];
        return NO;
     }
     return YES;
}