parsing – Android SAX parser not getting full text from between tags-ThrowExceptions

Exception or error:

I’ve created my own DefaultHandler to parse rss feeds and for most feeds it’s working fine, however, for ESPN, it is cutting off part of the article url due to the way ESPN formats it’s urls. An example of a full article url from ESPN..

http://sports.espn.go.com/nba/news/story?id=5189101&campaign=rss&source=ESPNHeadlines

The problem is for some reason the DefaultHandler characters method is only getting this from the tag that contains the above url.

http://sports.espn.go.com/nba/news/story?id=5189101

As you can see, it’s cutting everything off the url from the ampersand escape code and after. How can I get the SAX parser to not cut my string off at this escape code? For ref. here is my characters method..

 public void characters(char ch[], int start, int length) {

  String chars = (new String(ch).substring(start, start + length));

  try {
   // If not in item, then title/link refers to feed
   if (!inItem) {
    if (inTitle)
     currentFeed.title = chars;
   } else {
    if (inLink)
     currentArticle.url = new URL(chars);
    if (inTitle)
     currentArticle.title = chars;
    if (inDescription)
     currentArticle.description = chars;
    if (inPubDate)
     currentArticle.pubDate = chars;
    if (inEnclosure) {
    }
   }
  } catch (MalformedURLException e) {
   Log.e("RSSReader", e.toString());
  }
 }

Rob W.

How to solve:

As you can see, it’s cutting
everything off the url from the
ampersand escape code and after.

From the documentation of the characters() method:

The Parser will call this method to
report each chunk of character data.
SAX parsers may return all contiguous
character data in a single chunk, or
they may split it into several chunks;
however, all of the characters in any
single event must come from the same
external entity so that the Locator
provides useful information.

When I write SAX parsers, I use a StringBuilder to append everything passed to characters():

public void characters (char ch[], int start, int length) {
    if (buf!=null) {
        for (int i=start; i<start+length; i++) {
            buf.append(ch[i]);
        }
    }
}

Then in endElement(), I take the contents of the StringBuilder and do something with it. That way, if the parser calls characters() several times, I don’t miss anything.

###

@Override
public void startElement(String uri, String localName, String qName,
        Attributes attributes) throws SAXException {
    // TODO Auto-generated method stub
    sb=new StringBuilder();
    if(localName.equals("icon"))
    {
        iconflag=true;
    }
}

@Override
public void characters (char ch[], int start, int length) {
    if (sb!=null && iconflag == true) {
        for (int i=start; i<start+length; i++) {
            sb.append(ch[i]);
        }
    }
}

@Override
public void endElement(String uri, String localName, String qName)
        throws SAXException {
    // TODO Auto-generated method stub
    if(iconflag)
    {
        info.setIcon(sb.toString().trim());
        iconflag=false;
    }
}

So I figured it out, the code above is the solution.

###

I ran into this problem the other day, it turns out the reason for this is the CHaracters method is being called multiple times in case any of these Characters are contained in the Value:

"   &quot;
'   &apos;
<   &lt;
>   &gt;
&   &amp;

Also be careful about Linebreaks / newlines within the value!!!
If the xml is linewrapped without your controll the characters method wil also be called for each line that is in the statement, plus it will return the linebreak! (which you manually need to strip out in turn).

A sample Handler taking care of all these problems is this one:

 DefaultHandler handler = new DefaultHandler() {
   private boolean isInANameTag = false;
   private String localname;
   private StringBuilder elementContent;

   @Override
   public void startElement(String uri, String localName,String qName, Attributes attributes) throws SAXException {
    if (qname.equalsIgnoreCase("myfield")) {
      isInMyTag = true;
      this.localname = localname;
      this.elementContent = new StringBuilder();
    }
   }

   public void characters(char[] buffer, int start, int length) {
      if (isInMyTag) {
         String content = new String(ch, start, length);
         if (StringUtils.equals(content.substring(0, 1), "\n")) {
              // remove leading newline
              elementContent.append(content.substring(1));
         } else {
              elementContent.append(content);
         }
      }
   }

   public void endElement(String uri, String localName, String qName) throws SAXException {
     if (qname.equalsIgnoreCase("myfield")) {
       isInMyTag = false;
       // do something with elementContent.toString());
       System.out.println(elementContent.toString());
       this.localname = "";
     }
   }
}

I hope this helps.

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