忽略NSURLErrorDomain错误-999在UIWebView中不起作用 [英] Ignoring NSURLErrorDomain error -999 does not work in UIWebView

问题描述

我正在尝试避免在 UIWebView 的委托时返回错误时产生的问题。我在委托实现中有共同的解决方法（我在互联网上的任何地方看到过）

I'm trying to avoid the problem generated while UIWebView's delegate returns an error like that. I have the common workaround (I saw it anywhere in the Internet) in my delegate implementation

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {

    if ([error code] == NSURLErrorCancelled) return;
}

我遇到的问题是这并不总是有效。有时加载网页，另一次加载网页的一部分（标题，文本的一部分......），有几次不加载任何东西。

The problem I have is that this does not works always. Sometimes loads the web, another times loads parts of the web (the header, a part of the text...) and several times does not load anything.

有没有任何其他解决方案？存在任何正常运行的浏览器的开源实现？

Is there any other solution to this? Exists any open source implementation of a browser that works properly?

推荐答案

来自Apple文档：

NSURLErrorCancelled（-999）

NSURLErrorCancelled (-999)

取消异步加载时返回.Web Kit框架委托将收到此信息在加载资源上执行取消操作时出错。请注意，如果取消下载，NSURLConnection或NSURLDownload委托将不会收到此错误。

"Returned when an asynchronous load is canceled. A Web Kit framework delegate will receive this error when it performs a cancel operation on a loading resource. Note that an NSURLConnection or NSURLDownload delegate will not receive this error if the download is canceled."

因此，最有可能发生这种情况的原因是，在第一个请求完成之前，您需要加载一个请求，然后加载另一个请求（或同一个请求）。这可能发生。例如，如果你在 viewDidAppear这样的方法中调用 loadRequest （或 loadHTMLString ）：可以多次调用。如果你快速点击 UIWebView 中的2个链接，也会发生这种情况。

So, the most likely case for this to happen is for you to load a request and then another one (or the same one), before the first one is completed. This can happen. e.g., if you call loadRequest (or loadHTMLString) in a method like viewDidAppear: that can be called multiple times. This has also been reported to happen if you quickly tap 2 links in the UIWebView.

所以，一般建议是审查如何以及在何处调用 loadRequest （或 loadHTMLString ），并可能提供一些代码。

So, the general suggestion is to review how and where you call loadRequest (or loadHTMLString), and possibly provide some code.

为了解决这个问题，我建议将以下跟踪添加到您的网络视图代理中：

In order to troubleshoot this, I would suggest to add the following traces to your web view delegate:

- (void)webViewDidStartLoad:(UIWebView *)webView {
      NSLog(@"Starting to download request: %@", [webView.request.URL absoluteString]);
}

- (void)webViewDidFinishLoad:(UIWebView *)webView {
      NSLog(@"Finished downloading request: %@", [webView.request.URL absoluteString]);
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {

    if ([error code] == NSURLErrorCancelled)
      NSLog(@"Canceled request: %@", [webView.request.URL absoluteString]);
}

如果你检查输出，你应该更清楚地看到发生了什么。如果您粘贴输出，我们可以尝试进一步帮助您。

If you inspect the output, you should see more clearly what is going on. If you paste the output, we could try and help you further.

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