I'm trying to build a basic RSS Feed. I have no errors showing up in code however when I run the application it crashes with the following error:
FATAL EXCEPTION: AsyncTask #1java.lang.RuntimeException: An error occured while executing doInBackground()
This is my MainActivity.java code:
public class MainActivity extends ListActivity {List<String> headlines;List<String>links;@Overrideprotected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //initialize variables headlines = new ArrayList<String>(); links = new ArrayList<String>(); new PostTask().execute(); //binding data to list ArrayAdapter <String>adapter= new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, headlines); setListAdapter(adapter);}private InputStream getInputStream(URL url) { try{ return url.openConnection().getInputStream(); }catch(IOException e){ return null; }}@Overrideprotected void onListItemClick(ListView l, View v, int position, long id) { Uri uri = Uri.parse(links.get(position)); Intent intent = new Intent(Intent.ACTION_VIEW, uri); startActivity(intent);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.activity_main, menu); return true;}//ASYNCH CLASSprivate class PostTask extends AsyncTask<String, Integer, String>{ @Override protected String doInBackground(String... arg0) { try{ //link to data source URL url = new URL("http://feeds.pcworld.com/pcworld/latestnews"); //Set up parser XmlPullParserFactory factory = XmlPullParserFactory.newInstance(); factory.setNamespaceAware(false); XmlPullParser xpp = factory.newPullParser(); //get XML from input stream xpp.setInput(getInputStream(url), "UTF_8"); //Keep track of which tag inside of XML boolean insideItem = false; //Loop through the XML file and extract data required int eventType = xpp.getEventType(); while(eventType != XmlPullParser.END_DOCUMENT){ if(xpp.getName().equalsIgnoreCase("item")){ insideItem = true; }else if(xpp.getName().equalsIgnoreCase("title")){ if(insideItem){ //Get title headlines.add(xpp.nextText()); } }else if(xpp.getName().equalsIgnoreCase("link")){ if(insideItem){ //Get link links.add(xpp.nextText()); } }else if(eventType==XmlPullParser.END_TAG && xpp.getName().equalsIgnoreCase("item")){ insideItem = false; } eventType = xpp.next();//move to next element } }catch(MalformedURLException e){ e.printStackTrace(); }catch(XmlPullParserException e){ e.printStackTrace(); }catch(IOException e){ e.printStackTrace(); } return null; } public void onPostExecute(URL url) { }}}
Can anyone point me to where I am going wrong? Many thanks!
LOG CAT ERRORS:
01-11 17:27:50.061: E/AndroidRuntime(7746): FATAL EXCEPTION: AsyncTask #101-11 17:27:50.061: E/AndroidRuntime(7746): java.lang.RuntimeException: An error occured while executing doInBackground()01-11 17:27:50.061: E/AndroidRuntime(7746): at android.os.AsyncTask$3.done(AsyncTask.java:299)01-11 17:27:50.061: E/AndroidRuntime(7746): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)01-11 17:27:50.061: E/AndroidRuntime(7746): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)01-11 17:27:50.061: E/AndroidRuntime(7746): at java.util.concurrent.FutureTask.run(FutureTask.java:239)01-11 17:27:50.061: E/AndroidRuntime(7746): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)01-11 17:27:50.061: E/AndroidRuntime(7746): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)01-11 17:27:50.061: E/AndroidRuntime(7746): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)01-11 17:27:50.061: E/AndroidRuntime(7746): at java.lang.Thread.run(Thread.java:856)01-11 17:27:50.061: E/AndroidRuntime(7746): Caused by: java.lang.NullPointerException01-11 17:27:50.061: E/AndroidRuntime(7746): at com.example.simplerss.MainActivity$PostTask.doInBackground(MainActivity.java:89)01-11 17:27:50.061: E/AndroidRuntime(7746): at com.example.simplerss.MainActivity$PostTask.doInBackground(MainActivity.java:1)01-11 17:27:50.061: E/AndroidRuntime(7746): at android.os.AsyncTask$2.call(AsyncTask.java:287)01-11 17:27:50.061: E/AndroidRuntime(7746): at java.util.concurrent.FutureTask.run(FutureTask.java:234)01-11 17:27:50.061: E/AndroidRuntime(7746): ... 4 more
