Android SAXParser, parse into array and get child nodes

Question

I'm working on a small app that uses and xml file to print an ArrayList of chapters which in turn points to a specific html file.

I used this tutorial to get me started: http://www.anddev.org/novice-tutorials-f8/parsing-xml-from-the-net-using-the-saxparser-t353.html

My xml file looks something like this:

<chapters>
    <chapter title="Förutsättningar">
        <page title="Sida 3" url="sida_3.html" />
        <page title="Sida 4" url="sida_4.html" />
    </chapter>
</chapters>

Using the tutorial above I've managed to output each chapter node into an ArrayList with a onListItemClick function on each item. So far so good.

The problem I'm having is that I can't figure out how to get a specific child node and load the html file when I click an item. I'm pretty new to Android.

Any ideas? I would really appreciate ANY help on the subject.

Here's my source:

ParsingXML.java

public class ParsingXML extends ListActivity {
private final String MY_DEBUG_TAG = "XmlParser";
public String lang = null;

@Override
public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    setTitle("Lastsäkring");

    Bundle bundle = this.getIntent().getExtras();
    lang = bundle.getString("lang");

    Log.i("ParsingXML", "Chosen language: " + this.lang + ", Type: " + this.lang.getClass().getName());

    TextView tv = new TextView(this);

    try {
        SAXParserFactory spf = SAXParserFactory.newInstance();
        SAXParser sp = spf.newSAXParser();

        XMLReader xr = sp.getXMLReader();

        ExampleHandler myExampleHandler = new ExampleHandler();
        xr.setContentHandler(myExampleHandler);

        /*
         * If XML-file is located online (needs internet permissions in the manifest):
         * URL url = new URL("http://dev.houdini.se/android/demo.xml");
         * xr.parse(new InputSource(url.openStream()));
         */

        if(this.lang.equals("en"))
            xr.parse(new InputSource(this.getResources().openRawResource(R.raw.en_content)));
        else
            xr.parse(new InputSource(this.getResources().openRawResource(R.raw.sv_content)));

        ParsedExampleDataSet parsedExampleDataSet = myExampleHandler.getParsedData();                       
        this.setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, parsedExampleDataSet.toArrayList()));

    } catch(Exception e) {
        tv.setText("Error: " + e.getMessage());
        Log.e(MY_DEBUG_TAG, "XmlParseError", e);
        this.setContentView(tv);
    }
}

protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
    Context context = getApplicationContext();
    int duration = Toast.LENGTH_SHORT;

    CharSequence text = "Clicked position: " + position + ", id: " + id;
    Toast toast = Toast.makeText(context, text, duration);
    toast.show();


    /*switch( position )
    {
       case 0:                                  
                Bundle bundle = new Bundle();
                bundle.putString("WindowTitle", "TESTA");
                Intent intent = new Intent(this, TextPage.class);
                intent.putExtras(bundle);
                startActivity(intent);
                break;                  
       case 1:  
            Intent video = new Intent(this, Video.class);
            startActivity(video);
           break;

       case 2:  
            Intent swipe = new Intent(this, Swipe.class);
            startActivity(swipe);
          break;
    }*/
}

public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.options_menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection
    switch (item.getItemId()) {
        case R.id.settings:
            Intent prefsActivity = new Intent(getBaseContext(), Preferences.class);
            startActivity(prefsActivity);
            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}
}

ExampleHandler.java

public class ExampleHandler extends DefaultHandler {
private boolean in_chapters = false;
private boolean in_chapter = false;
private boolean in_page = false;

private ParsedExampleDataSet myParsedExampleDataSet = new ParsedExampleDataSet();

public ParsedExampleDataSet getParsedData() {
    return this.myParsedExampleDataSet;
}

@Override
public void startDocument() throws SAXException {
    this.myParsedExampleDataSet = new ParsedExampleDataSet();
}

@Override
public void endDocument() throws SAXException {
    // Nothing to do
}

@Override
public void startElement(String namespaceURI, String localName, String qName, Attributes atts) throws SAXException {
    if(localName.equals("chapters")) {
        this.in_chapters = true;
    } else if(localName.equals("chapter")) {
        this.in_chapter = true;
        String attrValue = atts.getValue("title");
        myParsedExampleDataSet.setExtractedString(attrValue);
    } else if(localName.equals("page")) {
        this.in_page = true;
    }
}

@Override
public void endElement(String namespaceURI, String localName, String qName) throws SAXException {
    if(localName.equals("chapters")) {
        this.in_chapters = false;
    } else if(localName.equals("chapter")) {
        this.in_chapter = false;
    } else if(localName.equals("page")) {
        this.in_page = false;
    }
}

@Override
public void characters(char ch[], int start, int length) {
    if(this.in_page == true) {
        myParsedExampleDataSet.setExtractedString(new String(ch, start, length));
    }
}

}

ParsedExampleDataSet.java

public class ParsedExampleDataSet {
private String extractedString = "";
private ArrayList<String> myArr = new ArrayList<String>();
private int extractedInt = 0;

public ArrayList<String> getExtractedString() {
    //return extractedString; Function Type = String
    return myArr;
}

public void setExtractedString(String extractedString) {
    //this.extractedString += extractedString + "\n";
    myArr.add(extractedString);
}

public int getExtractedInt() {
    return extractedInt;
}

public void setExtractedInt(int extractedInt) {
    this.extractedInt = extractedInt;
}

public String toString() {
    return "NODER\n" + this.extractedString;
}

public ArrayList<String> toArrayList() {
    return this.myArr;
}
}

Answer 1

First create proper data structure:

public class PageNode {
    public String title;
    public String url;
    /* Getters/setter/constructor etc. if you feel like*/
    public String toString() {
       return title;
    }
}

public class ChapterNode {
    public String title;
    public ArrayList<PageNode> pages = new ArrayList<PageNode>();
    /* Getters/setter/constructor etc. if you feel like*/
}

And parse the xml accordingly. Example:

ArrayList<ChapterNode> chapters = new ArrayList<ChapterNode>();
ChapterNode chapterNode = null;

public void startElement(String namespaceURI, String localName, String qName, Attributes atts) throws SAXException {
    if(localName.equals("chapters")) {
    } else if(localName.equals("chapter")) {
        chapterNode = new ChapterNode();
        chapterNode.title = atts.getValue("title");
    } else if(localName.equals("page")) {
        PageNode pageNode = new PageNode();
        pageNode.title = atts.getValue("title");
        pageNode.url = atts.getValue("url");
        chapterNode.pages.add(pageNode);
    }
}

@Override
public void endElement(String namespaceURI, String localName, String qName) throws SAXException {
    if(localName.equals("chapters")) {
    } else if(localName.equals("chapter")) {
        chapters.add(chapterNode);
        chapterNode = null;
    } else if(localName.equals("page")) {
    }
}

Then you can access the pageNode like this:

PageNode pageNode = chapterNode.pages.get(position);

And set adapter like this:

this.setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, chapterNode.pages));