如何更改UIWebView中的字符编码？ [英] How to change the character encoding in UIWebView?

问题描述

问题摘要：当浏览在iOS上未使用UIWebView明确指定正确字符编码的非英语网站时，无法正确显示该网页。

详细说明：由于UIWebView中的 loadRequest：方法将使用指定的编码在从Web服务器发送的字符集头或在HTML元标签中写入的字符集，并且默认为iso-8859-1（好，我不太确定），当charset没有指定，这导致非英语网站无法正常显示。

我尝试过改变UIWebView使用的字符集的方式，但唯一的方法是使用 loadData：MIMEType：

但是，使用 loadData不是一个好主意：MIMEType：textEncodingName：baseURL： + NSURLConnection而不是 loadRequest：，因为UIWebView不会调用委托方法 webView ：shouldStartLoadWithRequest：navigationType：对于框架，即使我们发现一个方法来获得通知当UIWebView加载框架，我们不能调用 loadData：MIMEType：textEncodingName：baseURL： code>加载框架内容，因为它将加载框架作为外部页面，如果我们这样做。

此外，我试图使用javascript黑客，但似乎该属性是只读的，不能更改。

  [webView stringByEvaluatingJavaScriptFromString：@document.characterSet ='utf-8';]; 
  

另一种解决方法是将元标记插入HTML，并要求UIWebView加载修改后的代码，上述框架问题也适用于此。

 < meta http-equiv =Content-Typecontent = html; charset = utf-8> 
  

问题：有更好的解决方案，可以更改字符编码在UIWebView中加载的网页，并正确处理框架？

解决方案

您可以通过手动加载HTML，然后将修改的内容加载到UIWebView中。

• 将不包含元标记的页面中的HTML手动加载到字符串中（例如使用 NSURLConnection ）


• 使用字符串操作，将适当的编码元标记插入手动加载的HTML


• 使用 loadHTMLString：

将您网络视图中的HTML设置为修改的字符串。



现在，这将适用于不包含链接的网页。如果它包含链接，那么你会发现，他们点击链接后，新页面将不会有您的修改。因此，您需要手动拦截所有点击。






• 实施UIWebView委托


• 实施方法 webView：shouldStartLoadWithRequest：navigationType：


• 在委托方法中，手动加载网址并修改内容，然后将其设置到UIWebView中，如上所示。





Summary of the problem: When browsing non-English sites that does not explicitly specify the correct character encoding with UIWebView on the iOS, the page cannot be displayed correctly.

Detailed explanation: As the loadRequest: method in UIWebView will use the encoding specified in the charset header sent from the web server or the charset written in the HTML meta tag, and default to iso-8859-1 (well, I am not too sure about this) when charset is not specified, which cause non-English sites cannot display properly.

I have tried to Google for a way to change the charset that the UIWebView use, but the only way is to use the loadData:MIMEType:textEncodingName:baseURL: method to specify the encoding name.

However, it is not a good idea to use loadData:MIMEType:textEncodingName:baseURL: + NSURLConnection instead of loadRequest:, because UIWebView won't call the delegate method webView:shouldStartLoadWithRequest:navigationType: for frames, and even if we found a way to get notified when UIWebView load a frame, we cannot call loadData:MIMEType:textEncodingName:baseURL: to load the frame content, because it will load the frame as the outer page if we do that.

Besides, I have tried to use a javascript hack, but seems that property is read-only and cannot be changed.

[webView stringByEvaluatingJavaScriptFromString:@"document.characterSet='utf-8';"];  

Another workaround is inserting a meta tag to the HTML, and ask UIWebView to load the modified code, but the frame problem mentioned above also apply here.

<meta http-equiv="Content-Type" content="text/html;charset=utf-8">

Question: Is there any better solution that can change the character encoding in a loaded webpage in UIWebView, and handle frames properly?

解决方案

You can do this by manually loading the HTML, modifying it, and then loading the modified content into the UIWebView.

• manually load the HTML from the page that doesn't include the meta tag, into a string (e.g. use NSURLConnection)
• using string manipulation, insert your appropriate encoding meta tag into the manually loaded HTML
• set the HTML in your web view to the modified string using loadHTMLString:

Now, this will work fine for a web page that contains no links. If it contains links, then you will find that after they click on a link, the new page will not have your modification in place. Therefore, you will need to manually intercept all of the clicks. Here's how you can do that:

• Implement a UIWebView delegate
• Implement the method webView:shouldStartLoadWithRequest:navigationType:
• In your delegate method, load the URL manually and modify the content before setting it into the UIWebView, as above.

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