出现android.os.NetworkOnMainThreadException异常

Question

当我运行我的android工程时，下边的代码中我得到了一个错误

URL url= new URL(urlToRssFeed);
SAXParserFactory factory =SAXParserFactory.newInstance();
SAXParser parser=factory.newSAXParser();
XMLReader xmlreader=parser.getXMLReader();
RssHandler theRSSHandler=new RssHandler();
xmlreader.setContentHandler(theRSSHandler);
InputSource is=new InputSource(url.openStream());
xmlreader.parse(is);
return theRSSHandler.getFeed();

错误是
android.os.NetworkOnMainThreadException

我怎么能够改掉这个错误？

我的版本是
SDK Platform Android 3.1,API 12, Revision 2 Eclipse SDK - 3.6.2

Answer 1

当一个应用程序试图在它的主线程执行网络操作的时候就会抛出这个异常。在AsyncTask中运行代码：

class RetreiveFeedTask extends AsyncTask<String, Void, RSSFeed> {

    private Exception exception;

    protected RSSFeed doInBackground(String... urls) {
        try {
            URL url= new URL(urls[0]);
            SAXParserFactory factory =SAXParserFactory.newInstance();
            SAXParser parser=factory.newSAXParser();
            XMLReader xmlreader=parser.getXMLReader();
            RssHandler theRSSHandler=new RssHandler();
            xmlreader.setContentHandler(theRSSHandler);
            InputSource is=new InputSource(url.openStream());
            xmlreader.parse(is);
            return theRSSHandler.getFeed();
        } catch (Exception e) {
            this.exception = e;
            return null;
        }
    }

    protected void onPostExecute(RSSFeed feed) {
    }
 }

 new RetreiveFeedTask().execute(urlToRssFeed);