android下对xml的解析

android 解析xml
1.使用SAXParser

    	try
    	{
    		
    	   URL url = new URL(urlToRssFeed);

           // create the factory
           SAXParserFactory factory = SAXParserFactory.newInstance();
           // create a parser
           SAXParser parser = factory.newSAXParser();

           // create the reader (scanner)
           XMLReader xmlreader = parser.getXMLReader();
           // instantiate our handler
           RSSHandler theRssHandler = new RSSHandler();
           // assign our handler
           xmlreader.setContentHandler(theRssHandler);
           // get our data via the url class
           InputSource is = new InputSource(url.openStream());
           // perform the synchronous parse           
           xmlreader.parse(is);
           // get the results - should be a fully populated RSSFeed instance, or null on error
           return theRssHandler.getFeed();
    	}
    	catch (Exception ee)
    	{
    		// if we have a problem, simply return null
    		return null;
    	}

handle片段
实现startDocument,endDocument,startElement,endElement四个方法
开始文档初始化数组，开始元素时初始化元素，完成元素时，把内容添加元素对象中，再把元素对象添加到对象数组中
最后返回对象数组

	RSSFeed getFeed()
	{
		return _feed;
	}
	

	public void startDocument() throws SAXException
	{
		// initialize our RSSFeed object - this will hold our parsed contents
		_feed = new RSSFeed();
		// initialize the RSSItem object - we will use this as a crutch to grab the info from the channel
		// because the channel and items have very similar entries..
		_item = new RSSItem();

	}
	public void endDocument() throws SAXException
	{
	}
	public void startElement(String namespaceURI, String localName,String qName, Attributes atts) throws SAXException
	{
		depth++;
		if (localName.equals("channel"))
		{
			currentstate = 0;
			return;
		}
		if (localName.equals("image"))
		{
			// record our feed data - we temporarily stored it in the item :)
			_feed.setTitle(_item.getTitle());
			_feed.setPubDate(_item.getPubDate());
		}
		if (localName.equals("item"))
		{
			// create a new item
			_item = new RSSItem();
			return;
		}
		if (localName.equals("title"))
		{
			currentstate = RSS_TITLE;
			return;
		}
		if (localName.equals("description"))
		{
			currentstate = RSS_DESCRIPTION;
			return;
		}
		if (localName.equals("link"))
		{
			currentstate = RSS_LINK;
			return;
		}
		if (localName.equals("category"))
		{
			currentstate = RSS_CATEGORY;
			return;
		}
		if (localName.equals("pubDate"))
		{
			currentstate = RSS_PUBDATE;
			return;
		}
		// if we don't explicitly handle the element, make sure we don't wind up erroneously 
		// storing a newline or other bogus data into one of our existing elements
		currentstate = 0;
	}
	
	public void endElement(String namespaceURI, String localName, String qName) throws SAXException
	{
		depth--;
		if (localName.equals("item"))
		{
			// add our item to the list!
			_feed.addItem(_item);
			return;
		}
	}
	

2.使用XmlPullParser来解析rss

       // TODO: switch to sax

        XmlPullParser xpp = Xml.newPullParser();
        xpp.setInput(in, null);  // null = default to UTF-8

        int eventType;
        String title = "";
        String link = "";
        String description = "";
        eventType = xpp.getEventType();
        while (eventType != XmlPullParser.END_DOCUMENT) {
            if (eventType == XmlPullParser.START_TAG) {
                String tag = xpp.getName();
                if (tag.equals("item")) {
                    title = link = description = "";
                } else if (tag.equals("title")) {
                    xpp.next(); // Skip to next element -- assume text is directly inside the tag
                    title = xpp.getText();
                } else if (tag.equals("link")) {
                    xpp.next();
                    link = xpp.getText();
                } else if (tag.equals("description")) {
                    xpp.next();
                    description = xpp.getText();
                }
            } else if (eventType == XmlPullParser.END_TAG) {
                // We have a comlete item -- post it back to the UI
                // using the mHandler (necessary because we are not
                // running on the UI thread).
                String tag = xpp.getName();
                if (tag.equals("item")) {
                    RssItem item = new RssItem(title, link, description);
                    mHandler.post(new ItemAdder(item));
                }
            }
            eventType = xpp.next();
        }