Obj-C decidePolicyForNavigationAction 没有被触发

Question

当 webview 加载新页面时，不会触发 decidePolicyForNavigationAction。 它在最初加载所有内容但之后永远不会被触发时起作用。

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction
decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler
{
    NSLog(@"decidePolicyForNavigationActionnavigationAction.request.URL.absoluteString:%@|", navigationAction.request.URL.absoluteString);
    
    
    if (kTestLocalHTML == 1) {
        decisionHandler(WKNavigationActionPolicyAllow);

        return;
    }
    
    
    NSURL *url = navigationAction.request.URL;
    if (url != nil) {
        
        
        //
        // TODO: Trim the url string below as well?
        //       No, because this is being trimmed already in the AppManager methods related to web view URL
        //
        
        NSString *urlString = url.absoluteString;
        WKNavigationType navType = navigationAction.navigationType;
        
        
        //
        // Display the club mobile native login page and log the user out
        // if the webview is about to load the blazor login page URL
        //
        if ([urlString isEqualToString:[AppManager getMobileLoginUrl]]) {
            self.appManager.userLoginDetails = nil;
            [self displayLoginPage];
            
            decisionHandler(WKNavigationActionPolicyCancel);
            return;
        }
        
        
        //
        // Check if link is tapped from webview and if URL string contains the
        // prepended identifier within the JavaScript injection which can be found in
        // "webViewDidFinishLoad" delegate method of webview
        //
        if (navType == WKNavigationTypeLinkActivated && [AppManager isWebViewURL_containsTargetBlank:urlString]) {
            
            //
            // Make sure to ignore the prepended identifier on the URL string
            // before opening it on an external browser
            //
            NSInteger targetBlankIdentifierLength = kIdentifier_TargetBlank.length;
            
            NSURL *url = [NSURL URLWithString:[urlString substringFromIndex:targetBlankIdentifierLength]];
            [[UIApplication sharedApplication] openURL:url];
            
            decisionHandler(WKNavigationActionPolicyCancel);
            return;
        }
        
        
        //
        // Check if url has custom scheme other than "http" & "https" (If is either one of the tags for Telephone "tel", Mail "mailto", SMS "sms", Web Calendar "webcal", etc.)
        //
        // Solution Reference: https://stackoverflow.com/questions/47040471/wkwebview-not-opening-custom-url-scheme-js-opens-custom-scheme-link-in-new-wind
        //      - (Answers of both "hstdt" & "mattblessed")
        //
        // NOTE: It seems loading telephone and mail links do not work when testing on an iOS simulator.
        //
        NSString *urlScheme = url.scheme;
        BOOL isCustomURLscheme = ( ! [urlScheme isEqualToString:@"http"] && ! [urlScheme isEqualToString:@"https"]);
        if (isCustomURLscheme) {
            
            NSURL *url = [NSURL URLWithString:urlString];
            [[UIApplication sharedApplication] openURL:url];
            
            decisionHandler(WKNavigationActionPolicyCancel);
            return;
        }
        
        
        //
        // Get reference to the current URL being requested so that if there
        // will be failure in loading the webview, we have a reference to that URL.
        //
        self.currentUrlRequest = navigationAction.request;
        
        
        // Check if web view URL contains a calendar file to download
        if ([AppManager isWebViewURL_containsCalendarDownload:urlString]) {
            
            //
            // Download and process calendar file either from Events or Dining module
            // and display "New Event" page where user can view its details, edit and save to device calendar
            //
            [self processCalendarFileAndDisplayEventPageWithURLrequest:self.currentUrlRequest];
            
            decisionHandler(WKNavigationActionPolicyCancel);
            return;
        }
        // Check if web view URL contains a PDF file attachment to download
        else if ([AppManager isWebViewURL_containsPDFAttachmentDownload:urlString]) {
            
            // Display document viewer page and pass few parameters for page customization (initial URL to load, navigation bar title)
            UIStoryboard *storyboard = [UIStoryboard storyboardWithName:kStoryboardName bundle:nil];
            UINavigationController *navigationController = [storyboard instantiateViewControllerWithIdentifier:kStoryboardID_OverlayBrowserNavigationController];
            OverlayBrowserViewController *vcOverlay = (OverlayBrowserViewController *)[navigationController topViewController];
            vcOverlay.initialURLtoLoad = urlString;
            vcOverlay.navigationBarTitle = [self getPDFDocumentNameFromURLString:urlString];
            [self presentViewController:navigationController animated:YES completion:nil];
            
            decisionHandler(WKNavigationActionPolicyCancel);
            return;
        }
    }
    
    decisionHandler(WKNavigationActionPolicyAllow);
}

这个 function 应该触发并检测 webview 是否正在加载 web 登录页面，如果是这种情况，它将注销用户并显示应用程序本机登录页面。 然而 function 在主屏幕最初加载后永远不会触发。

Answer 1

“你确定 web 页面实际上正在执行重定向，而不是像 Angular 这样的 SPA，它可能不会更新 URL？另外你如何设置 self.wkWebMain？ - RunLoop”

谢谢你，你是对的，网页充当 SPA，这就是 function 会在初始加载时首先调用但之后不会调用的原因。