Parsing XML on android using XML pull parser

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="90dp"
        android:text="Parse" />

</RelativeLayout>

MainActivity.java

package in.xmlparser;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		Button button = (Button) findViewById(R.id.button1);
		button.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View arg0) {
				new AsyncTask<Void, Void, Void>() {

					@Override
					protected Void doInBackground(Void... arg0) {
						readXmlFile("code.xml");
						return null;
					}

				}.execute();

			}
		});
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	public InputStream readFile(String fileName) throws FileNotFoundException,
			IOException {
		return new FileInputStream(Environment.getExternalStorageDirectory()
				+ "/" + fileName);
	}

	public void readXmlFile(String fileName) {
		try {
			if (fileName.isEmpty())
				throw new NullPointerException();
			readData(new XmlDataParseHelper(readFile(fileName)).getParser());
		} catch (IOException e) {
			e.printStackTrace();
		} catch (XmlPullParserException e) {
			e.printStackTrace();
		} catch (IllegalArgumentException e) {
			e.printStackTrace();
		}
	}

	public void readData(XmlPullParser parser) throws XmlPullParserException,
			IOException {
		int eventType = parser.getEventType();
		String tagName = "";
		Log.w("Developer", "Reading file...");
		while (eventType != XmlPullParser.END_DOCUMENT) {
			switch (eventType) {
			case XmlPullParser.START_DOCUMENT:
				Log.w("Developer", "Reading backup file...");
				break;
			case XmlPullParser.START_TAG:
				tagName = parser.getName();
				if (tagName.equals("countries")) {
					Log.w("XMLParse", "Start TAG countries");
					// do something when countries tag starts
				}
				if (tagName.equals("country")) {
					Log.w("XMLParse", "Start TAG country");
					// do some when country tag starts
				} else if (tagName.equals("name")) {
					// read tag value using XmlDataParseHelper class
					String countryName = XmlDataParseHelper.readTag(parser,
							"name");
					Log.w("XmlParser", "Country name : " + countryName);
				} else if (tagName.equals("phonecode")) {
					String countryPhoneCode = XmlDataParseHelper.readTag(
							parser, "phonecode");
					Log.w("XmlParser", "Country Phone code : "
							+ countryPhoneCode);
				} else if (tagName.equals("code")) {
					String countryCode = XmlDataParseHelper.readTag(parser,
							"code");
					Log.w("XmlParser", "Country code name : " + countryCode);
				}
				break;
			case XmlPullParser.END_TAG:
				tagName = parser.getName();
				if (tagName.equals("countries")) {
					// do something when counties tag is close.
				}
				break;
			}
			eventType = parser.next();
		}
		Log.w("Developer", "File parsing complete...");
	}
}

XmlDataParseHelper.java

package in.xmlparser;

import java.io.IOException;
import java.io.InputStream;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.util.Xml;

public class XmlDataParseHelper {

	private XmlPullParser parser;
	private static final String NULL = null;

	/**
	 * 
	 * @param in
	 * @throws XmlPullParserException
	 * @throws IOException
	 * @throws IllegalArgumentException
	 */
	public XmlDataParseHelper(InputStream in) throws XmlPullParserException,
			IOException, IllegalArgumentException {
		try {
			parser = Xml.newPullParser();
			parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
			parser.setInput(in, null);
			parser.nextTag();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * 
	 * @return XmlPullParser
	 */
	public XmlPullParser getParser() {
		return parser;
	}

	/**
	 * 
	 * @param parser
	 * @param tag
	 * @return String
	 * @throws IOException
	 * @throws XmlPullParserException
	 */
	public static String readTag(XmlPullParser parser, String tag)
			throws IOException, XmlPullParserException {
		String tagData = "";
		parser.require(XmlPullParser.START_TAG, NULL, tag);
		if (parser.next() == XmlPullParser.TEXT) {
			tagData = parser.getText();
			parser.nextTag();
		}
		parser.require(XmlPullParser.END_TAG, NULL, tag);
		return tagData;
	}

	/**
	 * 
	 * @param parser
	 * @param tag
	 * @param attributeName
	 * @return String
	 * @throws IOException
	 * @throws XmlPullParserException
	 */
	public static String readAttribute(XmlPullParser parser, String tag,
			String attributeName) throws IOException, XmlPullParserException {
		parser.require(XmlPullParser.START_TAG, NULL, tag);
		String attributeData = parser.getAttributeValue(NULL, attributeName);
		parser.nextTag();
		parser.require(XmlPullParser.END_TAG, NULL, tag);
		return attributeData;
	}

}