How to Build a RSS reader for Android?
I am new to android and i am trying to build a RSS reader for Android. I have built all the classes and XML files but its not giving the required output. Its just showing the message
No RSS feed available.
Please can some one suggest what should i do.
Here is the code which i took from the tutorial and tried to manipulate-
public final String RSSFEEDOFCHOICE = "http://blog.01synergy.com/feed/";
public final String tag = "RSSReader";
private RSSFeed feed = null;
/** Called when the activity is first created. */
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
// go get our feed!
feed = getFeed(RSSFEEDOFCHOICE);
// display UI
UpdateDisplay();
}
private RSSFeed getFeed(String urlToRssFeed)
{
try
{
// setup the url
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;
}
}
public boolean onCreateOptionsMenu(Menu menu)
{
super.onCreateOptionsMenu(menu);
menu.add(0,0,0, "Choose RSS Feed");
menu.add(0,1,0, "Refresh");
Log.i(tag,"onCreateOptionsMenu");
return true;
}
public boolean onOptionsItemSelected(Menu item){
switch (((View) item).getId()) {
case 0:
Log.i(tag,"Set RSS Feed");
return true;
case 1:
Log.i(tag,"Refreshing RSS Feed");
return true;
}
return false;
}
private void UpdateDisplay()
{
TextView feedtitle = (TextView) findViewById(R.id.feedtitle);
TextView feedpubdate = (TextView) findViewById(R.id.feedpubdate);
ListView itemlist = (ListView) findViewById(R.id.itemlist);
if (feed == null)
{
feedtitle.setText("No RSS Feed Available");
return;
}
feedtitle.setText(feed.getTitle());
feedpubdate.setText(feed.getPubDate());
ArrayAdapter<RSSItem> adapter = new ArrayAdapter<RSSItem>(this,android.R.layout.simple_list_item_1,feed.getAllItems());
itemlist.setAdapter(adapter);
itemlist.setOnItemClickListener(this);
itemlist.setSelection(0);
}
public void onItemClick(AdapterView parent, View v, int position, long id)
{
Log.i(tag,"item clicked! [" + feed.getItem(position).getTitle() + "]");
Intent itemintent = new Intent(this,ShowDescription.class);
Bundle b = new Bundle();
b.putString("title", feed.getItem(position).getTitle());
b.putString("description", feed.getItem(position).getDescription());
b.putString("link", feed.getItem(position).getLink());
b.putString("pubdate", feed.getItem(position).getPubDate());
itemintent.putExtra("android.intent.extra.INTENT", b);
startSubActivity(itemintent,0);
}
private void startSubActivity(Intent itemintent, int i) {
// TODO Auto-generated method stub
}
}
Answer
This is my first approach to RSS Reader, It's no so dynamic and has boilerplate code but worked well for myself.
Usage:
RssParser parser = new RssParser(feedUrl);
Log.i("LOG", "Description: " + parser.getItem(3).description); //4th item's description
Class:
package com.uncocoder.course.app.feed_reader;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import android.util.Log;
public class RssParser extends DefaultHandler {
private StringBuilder content;
private boolean inChannel;
private boolean inImage;
private boolean inItem;
private ArrayList<Item> items = new ArrayList<Item>();
private Channel channel = new Channel();
private Item lastItem;
public RssParser(String url) {
try {
SAXParserFactory spf = SAXParserFactory.newInstance();
SAXParser sp = spf.newSAXParser();
XMLReader xr = sp.getXMLReader();
URL sourceUrl = new URL(url);
xr.setContentHandler(this);
xr.parse(new InputSource(sourceUrl.openStream()));
}
catch (ParserConfigurationException e) {
e.printStackTrace();
}
catch (SAXException e) {
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
}
public class Item {
public String title;
public String description;
public String link;
public String category;
public String pubDate;
public String guid;
}
public class Channel {
public String title;
public String description;
public String link;
public String lastBuildDate;
public String generator;
public String imageUrl;
public String imageTitle;
public String imageLink;
public String imageWidth;
public String imageHeight;
public String imageDescription;
public String language;
public String copyright;
public String pubDate;
public String category;
public String ttl;
}
@Override
public void startDocument() throws SAXException {
Log.i("LOG", "StartDocument");
}
@Override
public void endDocument() throws SAXException {
Log.i("LOG", "EndDocument");
}
@Override
public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
if (localName.equalsIgnoreCase("image")) {
inImage = true;
}
if (localName.equalsIgnoreCase("channel")) {
inChannel = true;
}
if (localName.equalsIgnoreCase("item")) {
lastItem = new Item();
items.add(lastItem);
inItem = true;
}
content = new StringBuilder();
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
if (localName.equalsIgnoreCase("image")) {
inImage = false;
}
if (localName.equalsIgnoreCase("channel")) {
inChannel = false;
}
if (localName.equalsIgnoreCase("item")) {
inItem = false;
}
if (localName.equalsIgnoreCase("title")) {
if (content == null) {
return;
}
if (inItem) {
lastItem.title = content.toString();
} else if (inImage) {
channel.imageTitle = content.toString();
} else if (inChannel) {
channel.title = content.toString();
}
content = null;
}
if (localName.equalsIgnoreCase("description")) {
if (content == null) {
return;
}
if (inItem) {
lastItem.description = content.toString();
} else if (inImage) {
channel.imageDescription = content.toString();
} else if (inChannel) {
channel.description = content.toString();
}
content = null;
}
if (localName.equalsIgnoreCase("link")) {
if (content == null) {
return;
}
if (inItem) {
lastItem.link = content.toString();
} else if (inImage) {
channel.imageLink = content.toString();
} else if (inChannel) {
channel.link = content.toString();
}
content = null;
}
if (localName.equalsIgnoreCase("category")) {
if (content == null) {
return;
}
if (inItem) {
lastItem.category = content.toString();
} else if (inChannel) {
channel.category = content.toString();
}
content = null;
}
if (localName.equalsIgnoreCase("pubDate")) {
if (content == null) {
return;
}
if (inItem) {
lastItem.pubDate = content.toString();
} else if (inChannel) {
channel.pubDate = content.toString();
}
content = null;
}
if (localName.equalsIgnoreCase("guid")) {
if (content == null) {
return;
}
lastItem.guid = content.toString();
content = null;
}
if (localName.equalsIgnoreCase("url")) {
if (content == null) {
return;
}
channel.imageUrl = content.toString();
content = null;
}
if (localName.equalsIgnoreCase("width")) {
if (content == null) {
return;
}
channel.imageWidth = content.toString();
content = null;
}
if (localName.equalsIgnoreCase("height")) {
if (content == null) {
return;
}
channel.imageHeight = content.toString();
content = null;
}
if (localName.equalsIgnoreCase("language")) {
if (content == null) {
return;
}
channel.language = content.toString();
content = null;
}
if (localName.equalsIgnoreCase("copyright")) {
if (content == null) {
return;
}
channel.copyright = content.toString();
content = null;
}
if (localName.equalsIgnoreCase("ttl")) {
if (content == null) {
return;
}
channel.ttl = content.toString();
content = null;
}
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
if (content == null) {
return;
}
content.append(ch, start, length);
}
public Item getItem(int index) {
return items.get(index);
}
}