Android 3.1 Xml Parsing NullPointerException

I have code written for Android 2.2 that is supposed to parse xml from a webpage to a String. It works fine on an Android 2.2 emulator, but it gives me a NullPointerException on my Android 3.1 tablet. Here is the code:

Log.d("refreshMeta", "refreshing meta.");
            url = new URL("http://www.chineseoutreach.ca/media/Cstreaming.xml");
            URLConnection connection;
            connection = url.openConnection();

            HttpURLConnection httpConnection = (HttpURLConnection)connection;
            int responseCode = httpConnection.getResponseCode();

            if (responseCode == HttpURLConnection.HTTP_OK) {
                InputStream in = httpConnection.getInputStream();
                Log.d("Connection","connected");
                DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
                DocumentBuilder db = dbf.newDocumentBuilder();

                Document dom = db.parse(in);
                Element docEle = dom.getDocumentElement();
                NodeList nl = docEle.getElementsByTagName("nowplaying");
                Element entry = (Element)nl.item(0);

                try {
                    Element eartist = (Element)entry.getElementsByTagName("artist").item(0);
                sartist = eartist.getFirstChild().getNodeValue();
                Log.d("Artist",sartist);
                }
                catch(NullPointerException e) {
                    sartist = "";
                    Log.d("Connection",e.toString());
                }

Log on Android 3:

refreshmeta: refreshing meta.

Connection: Connected

Connection: java.lang.NullPointerException

EDIT This is the line that causes it. Element eartist = (Element)entry.getElementsByTagName("artist").item(0);

Edit 2

07-28 13:10:01.483: ERROR/Null(6189): my message

07-28 13:10:01.483: ERROR/Null(6189): java.lang.NullPointerException

07-28 13:10:01.483: ERROR/Null(6189): at com.ciam.app.CiamInfoActivity.refreshMeta(CiamInfoActivity.java:280)

07-28 13:10:01.483: ERROR/Null(6189): at com.ciam.app.CiamInfoActivity.access$0(CiamInfoActivity.java:257)

07-28 13:10:01.483: ERROR/Null(6189): at com.ciam.app.CiamInfoActivity$2.run(CiamInfoActivity.java:123) 07-28 13:10:01.483: ERROR/Null(6189): at java.lang.Thread.run(Thread.java:1020)

I suspect 开发者_开发问答that there are some differences between the way xml is parsed on android 2 and android 3. Any ideas? Thanks in advance.

There is a small mistake in your code. I don't really understand why it was working with android 2.1 emu, but it shouldn't have. Your problem was that you were doing a dom.getDocumentElement(). That function will return the base tag of your xml file which is in this case "nowplaying". And then you are doing a "docEle.getElementsByTagName("nowplaying");" over that.

If you want to be sure to get "nowplaying", you have to do a "dom.getElementsByTagName("nowplaying")".

Corrected version:

Document dom = db.parse(in);
Element docEle = (Element)dom.getElementsByTagName("nowplaying").item(0);
Element eartist = (Element)docEle.getElementsByTagName("artist").item(0);
Element etitle = (Element)docEle.getElementsByTagName("title").item(0);
Log.d("Artist", eartist.getTextContent());
Log.d("Title", etitle.getTextContent());

I'm not entirely sure, but it might have to do something with the link, since it can make the connection, but can't find the file... Try logging if it can find the xml the url points to.

If it can't find the file, try removing the .xml extension, perhaps it works.

I'm having the similar issue and stumbled upon this page. In my observation, the behaviour of getElementsByTagName is different among different android versions.

In ver 2, the result incudes itself if it has the specified tag. In your case, I guess the variable "docEle" has the tag "nowplaying" so it works fine.

In ver 3, the result only searches from the descendants so it doesn't include itself (docEle). So "nl" is really emptly.

According to the specification, ver 3 seems to be the expected behaviour. This seems so crucial but no one else mentioned this. Or, I may be wrong...