25

我NSString里面有大量的 HTML 文本。此字符串的长度超过 3.500.000 个字符。我怎样才能将这个 HTML 文本转换为NSString里面的纯文本。我正在使用扫描仪，但它工作得太慢了。任何想法 ？

4

7 回答 7

68

这取决于您所针对的 iOS 版本。由于 iOS7 有一个内置方法，它不仅可以去除 HTML 标签，还可以将格式设置为字符串：

Xcode 9/斯威夫特 4

if let htmlStringData = htmlString.data(using: .utf8), let attributedString = try? NSAttributedString(data: htmlStringData, options: [.documentType : NSAttributedString.DocumentType.html], documentAttributes: nil) {
    print(attributedString)
}

你甚至可以像这样创建一个扩展：

extension String {
    var htmlToAttributedString: NSAttributedString? {
        guard let data = self.data(using: .utf8) else {
            return nil
        }

        do {
            return try NSAttributedString(data: data, options: [.documentType : NSAttributedString.DocumentType.html, .characterEncoding: String.Encoding.utf8.rawValue], documentAttributes: nil)
        } catch {
            print("Cannot convert html string to attributed string: \(error)")
            return nil
        }
    }
}

请注意，此示例代码使用 UTF8 编码。您甚至可以创建一个函数而不是计算属性并将编码添加为参数。

斯威夫特 3

let attributedString = try NSAttributedString(data: htmlString.dataUsingEncoding(NSUTF8StringEncoding)!,
                                              options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
                                              documentAttributes: nil)

Objective-C

[[NSAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUTF8StringEncoding] options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute: [NSNumber numberWithInt:NSUTF8StringEncoding]} documentAttributes:nil error:nil];

如果您只需要删除和之间的所有内容<（>肮脏的方式！！！），如果字符串中有这些字符可能会出现问题，请使用以下命令：

- (NSString *)stringByStrippingHTML {
   NSRange r;
   NSString *s = [[self copy] autorelease];
   while ((r = [s rangeOfString:@"<[^>]+>" options:NSRegularExpressionSearch]).location != NSNotFound)
     s = [s stringByReplacingCharactersInRange:r withString:@""];
   return s;
}
于 2013-10-07T14:55:53.640 回答
16

我用扫描仪解决了我的问题，但我不是将它用于所有文本。在将所有部分连接在一起之前，我将它用于每 10.000 个文本部分。我的代码如下

-(NSString *)convertHTML:(NSString *)html {

    NSScanner *myScanner;
    NSString *text = nil;
    myScanner = [NSScanner scannerWithString:html];

    while ([myScanner isAtEnd] == NO) {

        [myScanner scanUpToString:@"<" intoString:NULL] ;

        [myScanner scanUpToString:@">" intoString:&text] ;

        html = [html stringByReplacingOccurrencesOfString:[NSString stringWithFormat:@"%@>", text] withString:@""];
    }
    //
    html = [html stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

    return html;
}

斯威夫特 4：

var htmlToString(html:String) -> String {
        var htmlStr =html;
        let scanner:Scanner = Scanner(string: htmlStr);
        var text:NSString? = nil;
        while scanner.isAtEnd == false {
            scanner.scanUpTo("<", into: nil);
            scanner.scanUpTo(">", into: &text);
            htmlStr = htmlStr.replacingOccurrences(of: "\(text ?? "")>", with: "");
        }
        htmlStr = htmlStr.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines);
        return htmlStr;
}
于 2013-10-07T15:38:28.510 回答
2

目标 C

+ (NSString*)textToHtml:(NSString*)htmlString
{
    htmlString = [htmlString stringByReplacingOccurrencesOfString:@"&quot;" withString:@"\""];
    htmlString = [htmlString stringByReplacingOccurrencesOfString:@"&apos;" withString:@"'"];
    htmlString = [htmlString stringByReplacingOccurrencesOfString:@"&amp;" withString:@"&"];
    htmlString = [htmlString stringByReplacingOccurrencesOfString:@"&lt;" withString:@"<"];
    htmlString = [htmlString stringByReplacingOccurrencesOfString:@"&gt;" withString:@">"];
    return htmlString;
}

希望这可以帮助！

于 2018-05-08T13:05:03.253 回答
1 
- (NSString *)stringByStrippingHTML:(NSString *)inputString
{
    NSMutableString *outString;

    if (inputString)
    {
        outString = [[NSMutableString alloc] initWithString:inputString];

        if ([inputString length] > 0)
        {
            NSRange r;

            while ((r = [outString rangeOfString:@"<[^>]+>|&nbsp;" options:NSRegularExpressionSearch]).location != NSNotFound)
            {
                [outString deleteCharactersInRange:r];
            }      
        }
    }

    return outString; 
}
于 2016-07-17T12:04:39.510 回答
1

对于 Swift 语言，

NSAttributedString(data:(htmlString as! String).dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true
            )!, options:[NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute: NSNumber(unsignedLong: NSUTF8StringEncoding)], documentAttributes: nil, error: nil)!
于 2015-08-17T06:20:21.940 回答
0

斯威夫特 4：

do {
   let cleanString = try NSAttributedString(data: htmlContent.data(using: String.Encoding.utf8)!,
                                                                      options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
                                                                      documentAttributes: nil)
} catch {
    print("Something went wrong")
}
于 2018-01-16T00:15:24.043 回答
0

通过将编码类型作为参数传递，它可以更通用，但作为这个类别的例子： 

@implementation NSString (CSExtension)

    - (NSString *)htmlToText {
        return [NSAttributedString.alloc
                initWithData:[self dataUsingEncoding:NSUnicodeStringEncoding]
                     options:@{NSDocumentTypeDocumentOption: NSHTMLTextDocumentType}
          documentAttributes:nil error:nil].string;
    }

@end
于 2018-12-10T04:41:41.130 回答