了解 decidePolicyForNavigationResponse 与用户交互

Question

我想在使用 WKWebView 打开 link 之前获得用户批准。 (Objective C) 我正在使用 decidePolicyForNaviagationResponse。

当它在 HTML 中遇到 link 时，它应该使用 UIAlertController 询问是否可以遵循 link（在最简单的实现中）。

但是它似乎是运行异步的，所以它首先打开 link 然后最终开始弹出警报。

我如何遇到 link，弹出警报然后打开 link 或不打开。我猜要么是关于块的一些我不理解的东西，比如完成处理程序，要么可能是使用信号量，尽管我对它们的适度尝试没有奏效。

我简化了代码以明确发生了什么。

谢谢！

static bool launchPermission = false;
@property (strong, nonatomic) WKWebViewConfiguration *theConfiguration;
@property (strong, nonatomic) WKWebView *webView;

.
.
.

_webView.navigationDelegate = self;
[_webView  loadRequest:nsrequest];
[self.view addSubview:_webView];

.
.
.

- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler{

        [self askPermissionForExternalLink];
        if (launchPermission)
        {
            decisionHandler(WKNavigationResponsePolicyAllow);
        }
        else
        {
            decisionHandler(WKNavigationResponsePolicyCancel);
        }
}


- (void) askPermissionForExternalLink
{
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Open external Web Conten?" message:@"Link is embedded with other content" preferredStyle:UIAlertControllerStyleAlert];

    UIAlertAction *cancelAction = [UIAlertAction
                                   actionWithTitle:NSLocalizedString(@"Cancel", @"Cancel action")
                                   style:UIAlertActionStyleCancel
                                   handler:^(UIAlertAction *action)
                                   {
                                       NSLog(@"Cancel action");
                                       [self cancelMethod];
                                       //return;
                                   }];

    UIAlertAction *okAction = [UIAlertAction
                               actionWithTitle:NSLocalizedString(@"OK", @"OK action")
                               style:UIAlertActionStyleDefault
                               handler:^(UIAlertAction *action)
                               {
                                   NSLog(@"OK action");
                                   //[self launchURL];
                                   [self OKMethod];
                               }];

    [alert addAction:cancelAction];
    [alert addAction:okAction];
    [alert show];
}

- (bool) cancelMethod
{
    launchPermission = false;
    return false;   
}

- (bool) OKMethod
{
    launchPermission = true;
    return true;    
}

Answer 1

您可以先在 decidePolicyForNavigationResponse 中使用块以这种方式尝试在块内进行 decideAction

- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler{



       void (^ launchPermission)(BOOL) = ^(BOOL isAllow)
        {
            if(isAllow)
            {
                decisionHandler(WKNavigationActionPolicyAllow);
            }
            else
            {
                decisionHandler(WKNavigationActionPolicyCancel);
            }
            return;
        };
        [self askPermissionForExternalLink];

    }

这里根据用户的选择发送 YES 或 NO 到 launchPermission 块

- (void) askPermissionForExternalLink
{
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Open external Web Conten?" message:@"Link is embedded with other content" preferredStyle:UIAlertControllerStyleAlert];

    UIAlertAction *cancelAction = [UIAlertAction
                                   actionWithTitle:NSLocalizedString(@"Cancel", @"Cancel action")
                                   style:UIAlertActionStyleCancel
                                   handler:^(UIAlertAction *action)
                                   {
                                       NSLog(@"Cancel action");
                                       launchPermission(NO);
                                       return;
                                   }];

    UIAlertAction *okAction = [UIAlertAction
                               actionWithTitle:NSLocalizedString(@"OK", @"OK action")
                               style:UIAlertActionStyleDefault
                               handler:^(UIAlertAction *action)
                               {
                                   NSLog(@"OK action");

                                   launchPermission(YES);
                                  return ;
                               }];

    [alert addAction:cancelAction];
    [alert addAction:okAction];
    [alert show];
}

了解 decidePolicyForNavigationResponse 与用户交互

Understanding decidePolicyForNavigationResponse with user interaction

objective-c

uialertcontroller

wkwebview