Parsing XML returns nothing

Question

I'm currently trying to parse some XML using XmlResourceParser and then show the information on a ListView using ArrayAdapter. The problem is, I don't get ant results.

My xml structure is like this:

<resources>

<categories>
    <animal>
        <word>
            <english>Animal</english>
            <french>Animal</french>
            <spanish>Animal</spanish>
            <portuguese>Animal</portuguese>
        </word>
    </animal>
    <transportation></transportation>
    <location></location>
    <clothing></clothing>
    <color></color>
    <people></people>
    <job></job>
    <society></society>
    <art></art>
    <beverages></beverages>
    <food></food>
    <home></home>
    <electronics></electronics>
    <body></body>
    <nature></nature>
    <material></material>
    <math></math>
    <directions></directions>
    <seasons></seasons>
    <numbers></numbers>
    <months></months>
    <days></days>
    <time></time>
    <verbs></verbs>
    <adjectives></adjectives>
</categories>

Now, each category will have different words on them but, at this moment I only want to get all the categories and show them in a ListView. To try and get all the categories I'm using the following code:

public class MainActivity extends ActionBarActivity {

private ListView list;
private ArrayList<String> arrayCategories;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    list = (ListView) findViewById(R.id.listView1);

    try {
        arrayCategories = parseCategories();

        ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(
                 this, 
                 R.id.listView1,
                 arrayCategories );

         list.setAdapter(arrayAdapter); 

    } catch (IOException e) {
        e.printStackTrace();
    }

}

And the parseCategories function is the following:

    private ArrayList<String> parseCategories() throws IOException {
    ArrayList<String> categories = new ArrayList<String>();
    XmlResourceParser parser = getResources().getXml(R.xml.database);

    try {
        int eventType = parser.getEventType();
        while (eventType != XmlPullParser.END_DOCUMENT) {
            if (eventType == XmlPullParser.START_TAG) {
                if (parser.getName().equals("categories")) {
                    categories.add(parser.nextText());
                }
            }

            eventType = parser.next();
        }
    } catch (XmlPullParserException e) {
        Log.e("XmlPullParserException", e.toString());
    }
    parser.close();

    return categories;
}

I'm still a little bit unexperienced when it comes to parse xml, can you guys help me with this one?

There is no "text" in the categories element, only more elements. (The only text is in the tags such as `Animal`, change `.equals("categories")` to `.equals("english")` to see.) — user2864740, Oct 17 '14 at 20:48
I this you should get help my already answer question. [Click here][1] [1]: http://stackoverflow.com/questions/26397647/how-to-make-rss-news-reader-application-in-android/26398110#26398110 — Danial Hussain, Oct 17 '14 at 20:49
So basically you're saying that I should 'hard code' the Categories, but how would I know which category does a particular word belongs to? — Cláudio Ribeiro, Oct 17 '14 at 21:01

score 1 · Answer 1 · edited May 23 '17 at 10:25

The problem is there is no "text" in the categories element; there are, however, many child elements.

The real task can be trivially summed up as:

How to get the names of all elements which are direct children of the categories element?

This problem is made a little bit complicated by XmlPullParser (using a DOM and/or XPath would be much easier), but it is doable. The trick here is to "skip" the subtrees by keeping a little depth counter; recursive functions would also work.

int eventType = parser.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT) {

  if (eventType == XmlPullParser.START_TAG
      && parser.getName().equals("categories")) { // catergories start

    int depth = 0;
    eventType = parser.next();
    while (!(depth == 0 && eventType == XmlPullParser.END_TAG)) { // end categories

      if (eventType == XmlPullParser.START_TAG) {
        if (depth == 0) {  // direct child of categories
          categories.add(parser.getName());
        }
        depth++;
      } else if (eventType == XmlPullParser.END_TAG) { // depth > 0
        depth--;
      }

      eventType = parser.next();
    }

  }

  eventType = parser.next();
}

Parsing XML returns nothing

1 Answers1