I have create an RSS Reader as in the following tutorial:http://techiedreams.com/android-rss-reader-part-3-action-bar-with-animated-item/
My problem is:when i load the list (with ListActivity.java), i sometimes get a NullPointerException, and i can see only the text in some listitems and the image in some other.
The logCat is:
04-07 22:01:26.900: W/System.err(22141): java.lang.NullPointerException04-07 22:01:26.900: W/System.err(22141): at com.td.rssreader.parser.DOMParser.parseXml(DOMParser.java:56)04-07 22:01:26.900: W/System.err(22141): at com.td.rssreader.ListActivity$2.run(ListActivity.java:115)04-07 22:01:26.900: W/System.err(22141): at java.lang.Thread.run(Thread.java:856)04-07 22:01:26.945: D/dalvikvm(22141): GC_CONCURRENT freed 887K, 10% free 13642K/15111K, paused 2ms+13ms, total 34ms04-07 22:01:56.425: W/IInputConnectionWrapper(22141): getSelectedText on inactive InputConnection04-07 22:01:56.425: W/IInputConnectionWrapper(22141): setComposingText on inactive InputConnection04-07 22:01:56.425: W/IInputConnectionWrapper(22141): getExtractedText on inactive InputConnection04-07 22:02:03.165: W/IInputConnectionWrapper(22141): showStatusIcon on inactive InputConnectionThe DOMParser class line 56 is :
theString = nchild.item(j).getFirstChild().getNodeValue();and the ListActivity line 115 is:
feed = tmpDOMParser.parseXml(feedLink);What i have to do in order to make it work..?i really can't find my error here :(
edit:
ListActivity.java
public class ListActivity extends Activity { RSSFeed feed; ListView lv; CustomListAdapter adapter; String feedLink; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.feed_list); // set the feed link for refresh feedLink = new SplashActivity().RSSFEEDURL; // Get feed form the file feed = (RSSFeed) getIntent().getExtras().get("feed"); // Initialize the variables: lv = (ListView) findViewById(R.id.listView); lv.setVerticalFadingEdgeEnabled(true); // Set an Adapter to the ListView adapter = new CustomListAdapter(this); lv.setAdapter(adapter); // Set on item click listener to the ListView lv.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) { // actions to be performed when a list item clicked int pos = arg2; Bundle bundle = new Bundle(); bundle.putSerializable("feed", feed); Intent intent = new Intent(ListActivity.this, DetailActivity.class); intent.putExtras(bundle); intent.putExtra("pos", pos); startActivity(intent); } }); } @Override public boolean onCreateOptionsMenu(Menu menu) { new MenuInflater(this).inflate(R.menu.activity_main, menu); return (super.onCreateOptionsMenu(menu)); } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.refresh_option: refreshList(item); return (true); case R.id.about_option: Toast.makeText(this, "RSS Reader!", Toast.LENGTH_SHORT).show(); return (true); } return super.onOptionsItemSelected(item); } public void refreshList(final MenuItem item) { /* Attach a rotating ImageView to the refresh item as an ActionView */ LayoutInflater inflater = (LayoutInflater) getApplication() .getSystemService(Context.LAYOUT_INFLATER_SERVICE); ImageView iv = (ImageView) inflater.inflate(R.layout.action_refresh, null); Animation rotation = AnimationUtils.loadAnimation(getApplication(), R.anim.refresh_rotate); rotation.setRepeatCount(Animation.INFINITE); iv.startAnimation(rotation); item.setActionView(iv); // trigger feed refresh: Thread thread = new Thread(new Runnable() { @Override public void run() { DOMParser tmpDOMParser = new DOMParser(); feed = tmpDOMParser.parseXml(feedLink); ListActivity.this.runOnUiThread(new Runnable() { @Override public void run() { if (feed != null && feed.getItemCount() > 0) { adapter.notifyDataSetChanged(); // lv.setAdapter(adapter); item.getActionView().clearAnimation(); item.setActionView(null); } } }); } }); thread.start(); } @Override protected void onDestroy() { super.onDestroy(); adapter.imageLoader.clearCache(); adapter.notifyDataSetChanged(); } // List adapter class class CustomListAdapter extends BaseAdapter { private LayoutInflater layoutInflater; public ImageLoader imageLoader; public CustomListAdapter(ListActivity activity) { layoutInflater = (LayoutInflater) activity .getSystemService(Context.LAYOUT_INFLATER_SERVICE); imageLoader = new ImageLoader(activity.getApplicationContext()); } @Override public int getCount() { // Set the total list item count return feed.getItemCount(); } @Override public Object getItem(int position) { return position; } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { // Inflate the item layout and set the views View listItem = convertView; int pos = position; if (listItem == null) { listItem = layoutInflater.inflate(R.layout.list_item, null); } // Initialize the views in the layout ImageView iv = (ImageView) listItem.findViewById(R.id.thumb); TextView tvTitle = (TextView) listItem.findViewById(R.id.title); TextView tvDate = (TextView) listItem.findViewById(R.id.date); // Set the views in the layout imageLoader.DisplayImage(feed.getItem(pos).getImage(), iv); tvTitle.setText(feed.getItem(pos).getTitle()); tvDate.setText(feed.getItem(pos).getDate()); return listItem; } }}DOMParser.java
public class DOMParser { private RSSFeed _feed = new RSSFeed(); public RSSFeed parseXml(String xml) { // _feed.clearList(); URL url = null; try { url = new URL(xml); } catch (MalformedURLException e1) { e1.printStackTrace(); } try { // Create required instances DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); // Parse the xml Document doc = db.parse(new InputSource(url.openStream())); doc.getDocumentElement().normalize(); // Get all <item> tags. NodeList nl = doc.getElementsByTagName("item"); int length = nl.getLength(); for (int i = 0; i < length; i++) { Node currentNode = nl.item(i); RSSItem _item = new RSSItem(); NodeList nchild = currentNode.getChildNodes(); int clength = nchild.getLength(); // Get the required elements from each Item for (int j = 1; j < clength; j = j + 2) { Node thisNode = nchild.item(j); String theString = null; String nodeName = thisNode.getNodeName(); theString = nchild.item(j).getFirstChild().getNodeValue(); if (theString != null) { if ("title".equals(nodeName)) { // Node name is equals to 'title' so set the Node // value to the Title in the RSSItem. _item.setTitle(theString); } else if ("description".equals(nodeName)) { _item.setDescription(theString); // Parse the html description to get the image url String html = theString; org.jsoup.nodes.Document docHtml = Jsoup .parse(html); Elements imgEle = docHtml.select("img"); _item.setImage(imgEle.attr("src")); }//description else if ("pubDate".equals(nodeName)) { // We replace the plus and zero's in the date with // empty string String formatedDate = theString.replace("+0000",""); _item.setDate(formatedDate); } if ("link".equals(nodeName)) { // Node name is equals to 'title' so set the Node // value to the Title in the RSSItem. _item.setLink(theString); } } } // add item to the list _feed.addItem(_item); } } catch (Exception e) { e.printStackTrace(); } // Return the final feed once all the Items are added to the RSSFeed // Object(_feed). return _feed; }}
