Objective c 通过用户交互理解decidePolicyForNavigationResponse

我希望在使用WKWebView打开链接之前获得用户批准。（目标C）我正在使用DecidepolicyFornavigationResponse

当它遇到HTML中的链接时，应该使用UIAlertController询问是否可以跟随该链接（在最简单的实现中）

但是，它似乎是异步运行的，所以它首先打开链接，然后最终会弹出警报

我如何遇到链接，弹出警报，然后打开或不打开链接。我猜测关于块的一些我不理解的东西，比如完成处理程序，或者可能使用信号量，尽管我对它们的适度尝试不起作用

我简化了代码，以清楚地了解发生了什么

谢谢大家!

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

.
.
.

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

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.
.

- (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;    
}

---

您可以在

decidePolicyForNavigationResponse

make decideAction中首先使用块来尝试这种方法

- (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];

    }

此处根据用户选择发送是或否以启动权限块

- (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];
}

---

您可以在

decidePolicyForNavigationResponse

make decideAction中首先使用块来尝试这种方法

- (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];

    }

此处根据用户选择发送是或否以启动权限块

- (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];
}

---

我会给你一个机会，让你知道，谢谢你。谢谢你这个工作！不过我有一个语法问题，因为有一件事我不明白。如何将launchpermission（）放入要在-（void）AskPermissionForExternalink中使用的正确范围？我必须将来自AskPermMisionForExternalink的代码嵌入到webView代码中（抱歉，我不知道如何将整个代码发布到这个简短的注释字段中），请参见fragment.void（^launchPermission）（BOOL）=^（BOOL isAllow）{if（isAllow）{decisionHandler（wkNavigationResponsePolicyLow）；}的下一条注释{decisionHandler（WKNavigationResponsePolicyCancel）；}return；}；/[self-AskPermissionForExternalink]；UIAlertController*alert=[UIAlertController alertControllerWithTitle:@“打开外部Web内容？”消息：@“链接嵌入了其他内容”preferredStyle:UIAlertControllerStyleAlert]；UIAlertAction*cancelAction=[UIAlertAction action WithTitle:NSLocalizedString（@“Cancel”、@“Cancel action”）等。我会尝试一下并让您知道，谢谢。谢谢您，这很有效！但我有一个语法问题，因为有一件事我不明白。如何将launchpermission（）放入正确的范围中，以便在-（void）中使用AskPermissionForExternalink？我必须将AskPermisionForExternalink中的代码嵌入到webView代码中（对不起，我不知道如何将整个代码发布到这个简短的注释字段中），请参见fragment.void（^launchPermission）（BOOL）=^（BOOL isAllow）{if（isAllow）{decisionHandler的下一条注释（wkNavigationResponsePolicyLow）；}其他{decisionHandler（WKNavigationResponsePolicyCancel）}返回；}；/[self-AskPermissionForExternalink]；UIAlertController*警报=[UIAlertController alertControllerWithTitle:@“打开外部Web内容？”消息：@“链接嵌入了其他内容”preferredStyle:UIAlertControllerStyleAlert]；UIAlertAction*cancelAction=[UIAlertAction actionWithTitle:NSLocalizedString（@“Cancel”、“Cancel action”）等。