iOS过滤Html标签[包含换行空格等特殊符号]

在今天在数据处理的时候，后台返回的json中有个字段是html内容，但是我这边只需要里面的文字部分，就写了如下这个方法：

- (NSString *)flattenHTML:(NSString *)html {
    
    //  过滤html标签
    NSScanner *theScanner;
    NSString *text = nil;
    theScanner = [NSScanner scannerWithString:html];
    while ([theScanner isAtEnd] == NO) {
        // find start of tag
        [theScanner scanUpToString:@"<" intoString:NULL] ;
        // find end of tag
        [theScanner scanUpToString:@">" intoString:&text] ;
        // replace the found tag with a space
        //(you can filter multi-spaces out later if you wish)
        html = [html stringByReplacingOccurrencesOfString:
                [NSString stringWithFormat:@"%@>", text] withString:@""];
    }
    //  过滤html中的\n\r\t换行空格等特殊符号
    NSMutableString *str1 = [NSMutableString stringWithString:html];
    for (int i = 0; i < str1.length; i++) {
        unichar c = [str1 characterAtIndex:i];
        NSRange range = NSMakeRange(i, 1);
        
        //  在这里添加要过滤的特殊符号
        if ( c == '\r' || c == '\n' || c == '\t' ) {
            [str1 deleteCharactersInRange:range];
            --i;
        }
    }
    html  = [NSString stringWithString:str1];
    return html;
}