一、将超文本转化为富文本

- (NSAttributedString *)htmlAttributeStringByHtmlString:(NSString *)htmlString
{
  NSAttributedString * attributeString;
  NSData * htmlData = [htmlString dataUsingEncoding:NSUTF8StringEncoding];
  NSDictionary * importParams = @{NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType,NSCharacterEncodingDocumentAttribute:[NSNumber numberWithInt:NSUTF8StringEncoding]};
  NSError * error = nil;
  attributeString = [[NSAttributedString alloc] initWithData:htmlData options:importParams documentAttributes:NULL error:&error];
  return attributeString;
}

二、 将富文本转化为超文本格式

- (NSString *)htmlStringByHtmlAttributeString:(NSAttributedString *)htmlAttributeString
{
  NSDictionary * exportParams = @{NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType,NSCharacterEncodingDocumentAttribute:[NSNumber numberWithInt:NSUTF8StringEncoding]};
  NSData * htmlData = [htmlAttributeString dataFromRange:NSMakeRange:(0,htmlAttributeString.length) documentAttributes:exportParams error:nil];
  htmlString = [[NSString alloc] initwithData:htmlData encoding:NSUTF8StringEncoding];
  return htmlString;
}