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;
    }
}

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;
    }
}

如果有人想知道，Drawnonward的解决方案在Swift中是这样的:

func webView(webView: UIWebView!, shouldStartLoadWithRequest request: NSURLRequest!, navigationType: UIWebViewNavigationType) -> Bool {
    if navigationType == UIWebViewNavigationType.LinkClicked {
        UIApplication.sharedApplication().openURL(request.URL)
        return false
    }
    return true
}

将这个添加到UIWebView委托:

(经过编辑以检查导航类型。你也可以通过file:// requests传递相对链接)

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
    if (navigationType == UIWebViewNavigationTypeLinkClicked ) {
        [[UIApplication sharedApplication] openURL:[request URL]];
        return NO;
    }

    return YES;
}

斯威夫特版本:

func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
        if navigationType == UIWebViewNavigationType.LinkClicked {
            UIApplication.sharedApplication().openURL(request.URL!)
            return false
        }
        return true
    }

Swift 3版本:

func webView(_ webView: UIWebView, shouldStartLoadWith request: URLRequest, navigationType: UIWebViewNavigationType) -> Bool {
    if navigationType == UIWebViewNavigationType.linkClicked {
        UIApplication.shared.openURL(request.url!)
        return false
    }
    return true
}

Swift 4版本:

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

更新

由于openURL在iOS 10中已弃用:

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
        if (navigationType == UIWebViewNavigationTypeLinkClicked ) {
            UIApplication *application = [UIApplication sharedApplication];
            [application openURL:[request URL] options:@{} completionHandler:nil];
            return NO;
        }

        return YES;
}

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。