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javaandroidandroid-networkingnetworkonmainthread

How can I fix 'android.os.NetworkOnMainThreadException'?


I got an error while running my Android project for RssReader.

Code:

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();

And it shows the below error:

android.os.NetworkOnMainThreadException

How can I fix this issue?


Solution

  • NOTE : AsyncTask was deprecated in API level 30.
    AsyncTask | Android Developers

    This exception is thrown when an application attempts to perform a networking operation on its main thread. Run your code in AsyncTask:

    class RetrieveFeedTask 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;
            } finally {
                is.close();
            }
        }
    
        protected void onPostExecute(RSSFeed feed) {
            // TODO: check this.exception
            // TODO: do something with the feed
        }
    }
    

    How to execute the task:

    In MainActivity.java file you can add this line within your oncreate() method

    new RetrieveFeedTask().execute(urlToRssFeed);
    

    Don't forget to add this to AndroidManifest.xml file:

    <uses-permission android:name="android.permission.INTERNET"/>