Introduction

In this article, you will learn about XML parsing with the pull parser
XML Parsing
XML parsing is a process of converting data from a server in a machine-readable form.
XML pull parser
The XML pull parser is an interface that defines the parsing functionality. It provides two key methods next() that provide access to high-level parsing events. The current event state of the parser can be determined by the geteventType() method. Initially, the parser lies in the START_DOCUMENT state.
The following are the events seen by next():
  • START_TAG:
    an XML start tag was read.

  • Text:
    Text content was read. The text content was retrieved using the getText() method.

  • END_TAG:
    A tag was read.

  • END_DOCUMENT:
    No more events are available.
Step 1
Create an XML file and write this:
  1. <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  2. xmlns:tools="http://schemas.android.com/tools"
  3. android:layout_width="match_parent"
  4. android:layout_height="match_parent"
  5. android:paddingLeft="@dimen/activity_horizontal_margin"
  6. android:paddingRight="@dimen/activity_horizontal_margin"
  7. android:paddingTop="@dimen/activity_vertical_margin"
  8. android:paddingBottom="@dimen/activity_vertical_margin"
  9. tools:context=".MainActivity">
  10. <ListView
  12. android:id="@android:id/list"
  14. android:layout_width="fill_parent"
  16. android:layout_height="wrap_content"/>
  18. </RelativeLayout>
Step 2
Create a Java file MainActivity.java and write this:
  1. import android.app.ListActivity;
  2. import android.app.ProgressDialog;
  3. import android.content.Context;
  4. import android.os.AsyncTask;
  5. import android.os.Bundle;
  6. import android.util.Log;
  7. import android.view.Menu;
  9. import org.apache.http.HttpEntity;
  10. import org.apache.http.HttpResponse;
  11. import org.apache.http.client.ClientProtocolException;
  12. import org.apache.http.client.methods.HttpPost;
  13. import org.apache.http.impl.client.DefaultHttpClient;
  14. import org.apache.http.util.EntityUtils;
  15. import org.w3c.dom.Document;
  16. import org.w3c.dom.Element;
  17. import org.w3c.dom.NodeList;
  18. import org.xmlpull.v1.XmlPullParser;
  19. import org.xmlpull.v1.XmlPullParserException;
  20. import org.xmlpull.v1.XmlPullParserFactory;
  22. import java.io.IOException;
  23. import java.io.StringReader;
  24. import java.io.UnsupportedEncodingException;
  26. public class MainActivity extends ListActivity {
  28. private static String BASE_URL = "http://maps.googleapis.com/maps/api/geocode/xml?address=NewDelhi&sensor=false";
  30. @Override
  31. protected void onCreate(Bundle savedInstanceState) {
  32. super.onCreate(savedInstanceState);
  33. setContentView(R.layout.activity_main);
  34. (new ProgressTask(MainActivity.this)).execute();
  35. }
  36. @Override
  37. public boolean onCreateOptionsMenu(Menu menu) {
  38. // Inflate the menu; this adds items to the action bar if it is present.
  39. getMenuInflater().inflate(R.menu.main, menu);
  40. return true;
  41. }
  43. public class ProgressTask extends AsyncTask<String, Void, Boolean> {
  45. private ProgressDialog dialog;
  46. private Context context;
  48. public ProgressTask(ListActivity activity) {
  49. Log.i("1", "Called");
  50. context = activity;
  52. dialog = new ProgressDialog(context);
  53. }
  54. protected void onPreExecute() {
  55. this.dialog.setMessage("Progress start");
  56. this.dialog.show();
  57. }
  58. @Override
  59. protected void onPostExecute(final Boolean success) {
  60. if (dialog.isShowing()) {
  61. dialog.dismiss();
  62. }
  63. }
  64. protected Boolean doInBackground(final String... args) {
  65. String xml = getXmlFromUrl(BASE_URL);
  66. // useParserType1(xml);
  67. useParserType2(xml);
  68. return null;
  69. }
  70. }
  72. //DOM Parser
  73. public void useParserType1(String xml){
  74. XmlParsingType1 parser = new XmlParsingType1();
  75. Document doc = parser.getDomElement(xml); // getting DOM element
  77. NodeList GeocodeResponse = doc.getElementsByTagName("location");
  79. for (int i = 0; i < GeocodeResponse.getLength(); i++) {
  80. Element e = (Element) GeocodeResponse.item(i);
  81. Log.i("xml", parser.getValue(e,"lat"));
  82. Log.i("xml", parser.getValue(e,"lng"));
  83. }
  84. }
  86. //XmlPull Parser
  87. public void useParserType2(String xml){
  88. try{
  89. Boolean flagLocation = false;
  90. Boolean flagLatitude = false;
  91. Boolean flagLongitude = false;
  92. XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
  93. factory.setNamespaceAware(true);
  94. XmlPullParser xpp = factory.newPullParser();
  96. xpp.setInput(new StringReader(xml));
  97. int eventType = xpp.getEventType();
  98. while (eventType != XmlPullParser.END_DOCUMENT) {
  99. if(eventType == XmlPullParser.START_DOCUMENT) {
  101. } else if(eventType == XmlPullParser.END_DOCUMENT) {
  103. } else if(eventType == XmlPullParser.START_TAG) {
  105. if (xpp.getName().equalsIgnoreCase("location")) flagLocation=true;
  106. if (flagLocation && xpp.getName().equalsIgnoreCase("lat")) flagLatitude=true;
  107. if (flagLocation && xpp.getName().equalsIgnoreCase("lng")) flagLongitude=true;
  109. } else if(eventType == XmlPullParser.END_TAG) {
  111. if (xpp.getName().equalsIgnoreCase("location")) flagLocation=false;
  112. if (flagLocation && xpp.getName().equalsIgnoreCase("lat")) flagLatitude=false;
  113. if (flagLocation && xpp.getName().equalsIgnoreCase("lng")) flagLongitude=false;
  115. } else if(eventType == XmlPullParser.TEXT) {
  118. if (flagLatitude)
  119. Log.i("Latitude: ", xpp.getText());
  120. if (flagLongitude)
  121. Log.i("Longitude: ", xpp.getText());
  122. }
  123. eventType = xpp.next();
  124. }
  126. }catch (XmlPullParserException e){
  127. e.printStackTrace();
  128. }catch (IOException e){
  129. e.printStackTrace();
  130. }
  131. }
  132. public String getXmlFromUrl(String url) {
  133. String xml = null;
  135. try {
  136. // defaultHttpClient
  137. DefaultHttpClient httpClient = new DefaultHttpClient();
  138. HttpPost httpPost = new HttpPost(url);
  140. HttpResponse httpResponse = httpClient.execute(httpPost);
  141. HttpEntity httpEntity = httpResponse.getEntity();
  142. xml = EntityUtils.toString(httpEntity);
  144. } catch (UnsupportedEncodingException e) {
  145. e.printStackTrace();
  146. } catch (ClientProtocolException e) {
  147. e.printStackTrace();
  148. } catch (IOException e) {
  149. e.printStackTrace();
  150. }
  151. // return XML
  152. return xml;
  153. }
  155. }
Step 3
Create another Java class file XMLParser.java and write this:
  1. import android.util.Log;
  2. import org.w3c.dom.Document;
  3. import org.w3c.dom.Element;
  4. import org.w3c.dom.Node;
  5. import org.w3c.dom.NodeList;
  6. import org.xml.sax.InputSource;
  7. import org.xml.sax.SAXException;
  8. import java.io.IOException;
  9. import java.io.StringReader;
  10. import javax.xml.parsers.DocumentBuilder;
  11. import javax.xml.parsers.DocumentBuilderFactory;
  12. import javax.xml.parsers.ParserConfigurationException;
  14. /**
  15. * Created by naveen on 19/06/13.
  16. */
  17. public class XmlParsingType1 {
  19. public Document getDomElement(String xml){
  20. Document doc = null;
  21. DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
  23. try {
  25. DocumentBuilder db = dbf.newDocumentBuilder();
  27. InputSource is = new InputSource();
  28. is.setCharacterStream(new StringReader(xml));
  29. doc = db.parse(is);
  31. } catch (ParserConfigurationException e) {
  32. Log.e("Error: ", e.getMessage());
  33. return null;
  34. } catch (SAXException e) {
  35. Log.e("Error: ", e.getMessage());
  36. return null;
  37. } catch (IOException e) {
  38. Log.e("Error: ", e.getMessage());
  39. return null;
  40. }
  41. // return DOM
  42. return doc;
  43. }
  45. public String getValue(Element item, String str) {
  46. NodeList n = item.getElementsByTagName(str);
  47. return this.getElementValue(n.item(0));
  48. }
  50. public final String getElementValue( Node elem ) {
  51. Node child;
  52. if( elem != null){
  53. if (elem.hasChildNodes()){
  54. for( child = elem.getFirstChild(); child != null; child = child.getNextSibling() ){
  55. if( child.getNodeType() == Node.TEXT_NODE ){
  56. return child.getNodeValue();
  57. }
  58. }
  59. }
  60. }
  61. return "";
  62. }
  63. }
Output
Clipboard03.jpg
See Logcat
Clipboard01.jpg