Can only parse TITLE tag -- LINK, DESCRIPTION, PUBDATE and others will not parse. (RSS / SAX)

Question

I'm new to android development and I have been struggling to parse more than one tag at a time and display it in a ListView.

I'm using SAX parser, here is my RssParseHandler code.

public class RssParseHandler extends DefaultHandler {
private List<RssItem> rssItems;
private RssItem currentMessage;
//private StringBuilder builder;
private boolean parseLink;
private boolean parseTitle;
private boolean parseDate;
private boolean parseDes;

public RssParseHandler() {
    rssItems = new ArrayList();
}

public List<RssItem> getItems() {


    return this.rssItems;
}


@Override
public void startElement(String uri, String localName, String name,
                         Attributes attributes) throws SAXException {
    super.startElement(uri, localName, name, attributes);
    if (localName.equalsIgnoreCase("item")) {
        this.currentMessage = new RssItem();
    } else if (localName.equalsIgnoreCase("title")) {
        //currentMessage.setTitle(builder.toString());
        parseTitle = true;
    } else if (localName.equalsIgnoreCase("link")) {
        //currentMessage.setLink(builder.toString());
        parseLink = true;
    } else if (localName.equalsIgnoreCase("description")) {
        //currentMessage.setDescription(builder.toString());
       parseDes = true;
        } else if (localName.equalsIgnoreCase("pubDate")) {
        //currentMessage.setDate(builder.toString());

        parseDate = true;
    }

    //parsing enclosure tag
    else if ("enclosure".equals(localName)) {
        // Get tags attributes number
        int attrsLength = attributes.getLength();
        for (int i = 0; i < attrsLength; i++) {
            String attrName = attributes.getQName(i);  // attribute name
            if ("url".equals(attrName))   // This tag has only one attribute but it is better to check it name is correct
                currentMessage.getLink();

        }

    }
}


@Override
public void endElement(String uri, String localName, String name)
        throws SAXException {


    super.endElement(uri, localName, name);
    if (this.currentMessage != null) {
        if (localName.equalsIgnoreCase("item")) {
            rssItems.add(currentMessage);
            //currentMessage = null;
        } else if (localName.equalsIgnoreCase("link")) {
            //currentMessage.setLink(builder.toString());
            //parseLink = false;
       } else if (localName.equalsIgnoreCase("description")) {
            //currentMessage.setDescription(builder.toString());
          //parseDes = false;
        } else if (localName.equalsIgnoreCase("pubDate")){

            //currentMessage.setDate(builder.toString());
            parseDate = false;
        } else if (localName.equalsIgnoreCase("title")) {
            //currentMessage.setTitle(builder.toString());
            parseTitle = false;
        }
        //builder.setLength(0);
    }
}

@Override
public void characters(char[] ch, int start, int length)
        throws SAXException {
    super.characters(ch, start, length);
    //builder.append(ch, start, length);
    if (parseTitle) {
        if (currentMessage != null)
            currentMessage.setTitle(new String(ch, start, length));

    } else if (parseLink) {
        if (currentMessage != null) {
            currentMessage.setLink(new String(ch, start, length));
            //parseLink = false;
        }
    } else if (parseDes) {
        if (currentMessage != null)
            currentMessage.setDescription(new String(ch, start, length));
            //parseLink = false;


    } else if (parseDate) {
        if (currentMessage != null) {
            currentMessage.setDate(new String(ch, start, length));
            //currentMessage.setDate(new String(ch, start, length));
            //parseDesc = false;
        }
        }
    }

}

Here is the code for the Listview:

public class ReaderAppActivity extends Fragment {

    private ReaderAppActivity local;
    private ListView mList;
    /**
     * This method creates main application view
     */
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        //super.onCreate(savedInstanceState);
        // Set view
        //setContentView(R.layout.fragment_rss);





        local = this;
        //int position = getArguments().getInt("position");

       // String url = getArguments().getString("url");

        // List of rivers
        String[] menus = getResources().getStringArray(R.array.menus);

        // Creating view corresponding to the fragment
        View v = inflater.inflate(R.layout.fragment_rss, container, false);
        // Set reference to this activity
        //local = this;

        GetRSSDataTask task = new GetRSSDataTask();

        // Start download RSS task
        task.execute("http://thechurchofwhatshappeningnow.libsyn.com/rss");
        //task.execute(url);

        // Debug the thread name
        Log.d("ITCRssReader", Thread.currentThread().getName());

        //mList = (ListView) findViewById(R.id.rssListMainView);

        return v;
    }

    private class GetRSSDataTask extends AsyncTask<String, Void, List<RssItem> > {
        @Override
        protected List<RssItem> doInBackground(String... urls) {

            // Debug the task thread name
            Log.d("ITCRssReader", Thread.currentThread().getName());

            try {
                // Create RSS reader
                RssReader rssReader = new RssReader(urls[0]);

                // Parse RSS, get items
                return rssReader.getItems();

            } catch (Exception e) {
                Log.e("ITCRssReader", e.getMessage());
            }


            return null;
        }

        @Override
        protected void onPostExecute(List<RssItem> result) {

            // Get a ListView from main view
            ListView mList = (ListView) getView().findViewById(R.id.rssListMainView);

            // Create a list adapter
            ArrayAdapter<RssItem> adapter = new ArrayAdapter<RssItem>(getActivity(),R.layout.rss_text, result);
            //ArrayAdapter<RssItem> adapter = new ArrayAdapter<RssItem>(getActivity(),R.layout.fragment_rss, result);
            // Set list adapter for the ListView
            mList.setAdapter(adapter);

            // Set list view item click listener
            mList.setOnItemClickListener(new ListListener(result, getActivity()));




        }
    }
}

What am I doing wrong? I can't figure it out. I would like to parse, the link, description, pubDate, and pass them into the ListView. Ideally I would only display the title and episode number in the listview, and pass the other tags into String, so I can display them when I click an item in the listView.

I've created another class called SingleMenuItem to be called when I click an item in the ListView, it's just filler code right now, it does not display anything because the items aren't parsed.

Any help would be appreciated. Here is a RSS link to the feed:

public class SingleMenuItem  extends Activity {

    // XML node keys
    static final String KEY_NAME = "name";
    static final String KEY_DATE = "pubdate";
    static final String KEY_DESC = "description";
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.single_list_item);

        // getting intent data
        Intent in = getIntent();

        // Get XML values from previous intent
        String name = in.getStringExtra(KEY_NAME);
        String date = in.getStringExtra(KEY_DATE);
        String description = in.getStringExtra(KEY_DESC);

        // Displaying all values on the screen
        TextView lblName = (TextView) findViewById(R.id.name_label);
        TextView lblDate = (TextView) findViewById(R.id.date_label);
        TextView lblDesc = (TextView) findViewById(R.id.description_label);

        lblName.setText(name);
        lblDate.setText(date);
        lblDesc.setText(description);
    }
}

Here is the code for my ReaderAppActivty that puts the results of the parsing into the ListView:

public class ReaderAppActivity extends Fragment {

private ReaderAppActivity local;
private ListView mList;
/**
 * This method creates main application view
 */
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    //super.onCreate(savedInstanceState);
    // Set view
    //setContentView(R.layout.fragment_rss);





    local = this;
    //int position = getArguments().getInt("position");

   // String url = getArguments().getString("url");

    // List of rivers
    String[] menus = getResources().getStringArray(R.array.menus);

    // Creating view corresponding to the fragment
    View v = inflater.inflate(R.layout.fragment_rss, container, false);
    // Set reference to this activity
    //local = this;

    GetRSSDataTask task = new GetRSSDataTask();

    // Start download RSS task
    task.execute("http://thechurchofwhatshappeningnow.libsyn.com/rss");
    //task.execute(url);

    // Debug the thread name
    Log.d("ITCRssReader", Thread.currentThread().getName());

    //mList = (ListView) findViewById(R.id.rssListMainView);

    return v;
}

private class GetRSSDataTask extends AsyncTask<String, Void, List<RssItem> > {
    @Override
    protected List<RssItem> doInBackground(String... urls) {

        // Debug the task thread name
        Log.d("ITCRssReader", Thread.currentThread().getName());

        try {
            // Create RSS reader
            RssReader rssReader = new RssReader(urls[0]);

            // Parse RSS, get items
            return rssReader.getItems();

        } catch (Exception e) {
            Log.e("ITCRssReader", e.getMessage());
        }


        return null;
    }

    @Override
    protected void onPostExecute(List<RssItem> result) {

        // Get a ListView from main view
        ListView mList = (ListView) getView().findViewById(R.id.rssListMainView);

        // Create a list adapter
        ArrayAdapter<RssItem> adapter = new ArrayAdapter<RssItem>(getActivity(),R.layout.rss_text, result);
        //ArrayAdapter<RssItem> adapter = new ArrayAdapter<RssItem>(getActivity(),R.layout.fragment_rss, result);
        // Set list adapter for the ListView
        mList.setAdapter(adapter);

        // Set list view item click listener
        mList.setOnItemClickListener(new ListListener(result, getActivity()));




    }
}

}

Answer 1

Based on the amount of commented-out code in your RssParseHandler, you've clearly been struggling with this for a bit, and some early attempts were closer to right than what you've got now.

The issue with your current code appears to be that you're not consistently resetting the booleans that drive which part of the item you're setting. Debugging through it, I saw it setting a date into the link field at some point.

But you're actually doing some of that setting in the wrong method, as the characters method doesn't necessarily give you the full contents of the tag. You need to use a Stringbuilder, and I can see from commented-out code that you tried that at some point.

If you collect the text in a stringbuilder and do all the setting in the endElement method, you don't really need the booleans at all, as the endElement method has knowledge of which tag you're ending.

Here's a working version that's perhaps not too far from something you had at some point but which gets rid of all those flag fields.

public class RssParseHandler extends DefaultHandler {
    private List<RssItem> rssItems;
    private RssItem currentMessage;
    private StringBuilder builder;

    public RssParseHandler() {
        rssItems = new ArrayList<>();
        builder = new StringBuilder();
    }

    public List<RssItem> getItems() {
        return this.rssItems;
    }

    @Override
    public void startElement(String uri, String localName, String name,
                             Attributes attributes) throws SAXException {
        super.startElement(uri, localName, name, attributes);
        builder.setLength(0);
        if (localName.equalsIgnoreCase("item")) {
            this.currentMessage = new RssItem();
        }
    }

    @Override
    public void endElement(String uri, String localName, String name)
            throws SAXException {

        super.endElement(uri, localName, name);
        if (this.currentMessage != null) {
            if (localName.equalsIgnoreCase("item")) {
                rssItems.add(currentMessage);
                currentMessage = null;
            } else if (localName.equalsIgnoreCase("link")) {
                currentMessage.setLink(builder.toString());
            } else if (localName.equalsIgnoreCase("description")) {
                currentMessage.setDescription(builder.toString());
            } else if (localName.equalsIgnoreCase("pubDate")){
                currentMessage.setDate(builder.toString());
            } else if (localName.equalsIgnoreCase("title")) {
                currentMessage.setTitle(builder.toString());
            }
        }
    }

    @Override
    public void characters(char[] ch, int start, int length)
            throws SAXException {
        super.characters(ch, start, length);
        builder.append(ch, start, length);
    }

}