Show Progress Dialog inside AsyncTask in Android

private class performBackgroundTask extends AsyncTask < Void, Void, Void > 
     {
        private ProgressDialog pdia;

        @Override
        protected void onPreExecute(){
           super.onPreExecute();
                pdia = new ProgressDialog(FriendList.this);
                pdia.setMessage("Loading...");
                pdia.show();   
        }

        @Override
        protected Void doInBackground(Void... params) {
            // TODO Auto-generated method stub
            asybcTastRun = new AsyncFacebookRunner(LoginActivity.facebook);
            asybcTastRun.request("me/friends", new FriendCallback());
            return null;
        }

         protected void onPostExecute(String result){
              // super.onPostExecute(result);
                    pdia.dismiss();
            }
      }

Email Validation Check In Android

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Util {
   
    public static boolean isEmailValid(String email) {
        boolean isValid = false;

        String expression = "^[\\w\\.-]+@([\\w\\-]+\\.)+[A-Z]{2,4}$";
        CharSequence inputStr = email;

        Pattern pattern = Pattern.compile(expression, Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher(inputStr);
        if (matcher.matches()) {
            isValid = true;
        }
        return isValid;
}
}

DOM Parsing Example For Get And Post Values In Android

 Hope this will help you..:)

Here two class DOMParsingTestingActivity and XMLParser are used..

Class:DOMParsingTestingActivity

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class DOMParsingTestingActivity extends Activity
{
    String deviceid;
    String    mailing_address_value;
    String    phone_number_value;
    String first_name_value;
    String last_name_value;
    String    email_address_value;
    boolean show=false;
    String response = null; 
    String url2;
    String email_address_edit;
    String lastname_edit;
    String    phone_number_edit;
    String result1;
    String first_name_edit;
    Button savebuttton,backbton;
    EditText first_name;
    EditText last_name;
    EditText email_address;
    EditText  phone_number;
    EditText mailing_address;
    String  mailing_address_edit;
   
    String KEY_Result = "Result";
    String KEY_love_rnr = "LoveRnR";
    String xml;
    String id;
    String urlshow;
    SharedPreferences mypref;
   
   
   
    String KEY_Userdetail="UsersDetails";
    String KEY_Firstname="FirstName";
    String KEY_Lastname="LastName";
    String KEY_Emailaddress="EmailAddress";
    String KEY_Mailingaddress="MailingAddress";
    String KEY_Phonenumber="PhoneNumber";
   
    ArrayList<String> user_detail_list;
    ArrayList<String> first_name_list;
    ArrayList<String> last_name_list;
    ArrayList<String> email_address_list;
    ArrayList<String> phone_number_list;
    ArrayList<String> mailing_address_list;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        deviceid=android.provider.Settings.System.getString(DOMParsingTestingActivity.this.getContentResolver(), android.provider.Settings.Secure.ANDROID_ID);
        mypref = PreferenceManager.getDefaultSharedPreferences(this);
        first_name=(EditText)findViewById(R.id.first_nameeditbox);
        last_name=(EditText)findViewById(R.id.last_nameeditbox);
        email_address=(EditText)findViewById(R.id.email_addeditbox);
        phone_number=(EditText)findViewById(R.id.phone_number_editprofile);
        mailing_address=(EditText)findViewById(R.id.mailing_addeditbox);
        savebuttton=(Button)findViewById(R.id.savebtnid);
        backbton=(Button)findViewById(R.id.backbtnid);
        //id=mypref.getString("Userid", "");
        //static value response
        id=String.valueOf(6);
        user_detail_list=new ArrayList<String>();
        first_name_list=new ArrayList<String>();
       
       
        last_name_list=new ArrayList<String>();
        email_address_list=new ArrayList<String>();
        phone_number_list=new ArrayList<String>();
       
       
        mailing_address_list=new ArrayList<String>();
        urlshow="Enter your url /showdetails.php?user_id="+id;
        XMLParser parser=new XMLParser();   
        String xml = parser.getXmlFromUrl(urlshow);
        Log.e("SplashScreen=",""+xml);
        Document doc = parser.getDomElement(xml);
       
       
        NodeList nl = doc.getElementsByTagName(KEY_Userdetail);
        for (int i=0; i<nl.getLength();i++)
        {
        Element e = (Element) nl.item(i);
        user_detail_list.add(parser.getValue(e, KEY_Userdetail));   
        first_name_list.add(parser.getValue(e, KEY_Firstname));   
        last_name_list.add(parser.getValue(e, KEY_Lastname));
        email_address_list.add(parser.getValue(e, KEY_Emailaddress));
        phone_number_list.add(parser.getValue(e,KEY_Phonenumber));
        mailing_address_list.add(parser.getValue(e,KEY_Mailingaddress));
        first_name_value=parser.getValue(e, KEY_Firstname).toString().trim();
        last_name_value=parser.getValue(e, KEY_Lastname).toString().trim();
        email_address_value=parser.getValue(e, KEY_Emailaddress).toString().trim();
        mailing_address_value=parser.getValue(e, KEY_Mailingaddress).toString().trim();
        phone_number_value=parser.getValue(e, KEY_Phonenumber).toString().trim();
   
        first_name.setText(String.valueOf(first_name_value));
        last_name.setText(String.valueOf(last_name_value));
        email_address.setText(String.valueOf(email_address_value));
        phone_number.setText(String.valueOf(phone_number_value));
        mailing_address.setText(String.valueOf(mailing_address_value));
        Log.e("",""+first_name_value);
        Log.e("",""+last_name_value);
        }
        savebuttton.setOnClickListener(new OnClickListener()
        {
        public void onClick(View paramView)       
        {
        save();   
            }
        });
        backbton.setOnClickListener(new OnClickListener() {
           
            public void onClick(View paramView)
            {
            Intent in=new Intent(DOMParsingTestingActivity.this,DOMParsingTestingActivity.class);   
            startActivity(in);
            }
        });
        }
       public void save()
        {
       first_name_edit=first_name.getEditableText().toString().trim();
       lastname_edit=last_name.getEditableText().toString().trim();
       email_address_edit=email_address.getEditableText().toString().trim();
       phone_number_edit=phone_number.getEditableText().toString().trim();
       mailing_address_edit=mailing_address.getEditableText().toString().trim();
       if(first_name_edit.equalsIgnoreCase("")|| lastname_edit.equalsIgnoreCase("")|| email_address_edit.equalsIgnoreCase("")|| phone_number_edit.equalsIgnoreCase("")||mailing_address_edit.equalsIgnoreCase(""))
       {  
       Toast.makeText(DOMParsingTestingActivity.this,"Please enter all the fields",Toast.LENGTH_LONG).show();
       }
       else
       {
       boolean  isValidEmail = Util.isEmailValid(email_address_edit);
       boolean callMethod = true;
       if(isValidEmail == false)
        {
        callMethod = false;
        Toast.makeText(DOMParsingTestingActivity.this, "Please enter a valid email address.", Toast.LENGTH_LONG).show();
        }
       if(phone_number_edit.length()<10)
       {
           callMethod = false;
       Toast.makeText(DOMParsingTestingActivity.this, "Please enter valid phone number",Toast.LENGTH_LONG).show();
       }
        if(callMethod)
       {
       url2="Enter your url /updateuser.php?user_id="+id+"&last_name="+lastname_edit+"&first_name="+first_name_edit+"&email_address="+email_address_edit+"&phone_number="+phone_number_edit+"&mailing_address="+mailing_address_edit+"&token_id="+deviceid;
             HttpURLConnection connection;
             OutputStreamWriter request = null;
              try
               {
               URL  url = new URL(url2);
               Log.i("URL", "url is "+url.toString());
               Log.e("",""+url);
              
               connection = (HttpURLConnection) url.openConnection();
               connection.setDoOutput(true);
               connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
               connection.setRequestMethod("POST");   
               request = new OutputStreamWriter(connection.getOutputStream());
               request.write(url2);
               request.flush();
               request.close();           
               String line = "";              
               InputStreamReader isr = new InputStreamReader(connection.getInputStream());
               BufferedReader reader = new BufferedReader(isr);
               StringBuilder sb = new StringBuilder();
               while ((line = reader.readLine()) != null)
                 {
               sb.append(line + "\n");
                  }             
               response = sb.toString();         
               Log.e("ResponseRelation=",""+response);
               Toast.makeText(DOMParsingTestingActivity.this,"Saved sucessfully.",Toast.LENGTH_LONG).show();
               isr.close();
               reader.close();
                 }
              catch(IOException e)
                 {    
                 }
           }
        }
}
}

Class:XMLParser

import java.io.IOException;
import java.io.StringReader;
import java.io.UnsupportedEncodingException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import android.util.Log;

public class XMLParser
{
    String xml = null;
    Document doc = null;
    /**
     * Getting XML from URL making HTTP request
     * @param url string
     * */
    public String getXmlFromUrl(String url)
    {
        try
        {
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            xml = EntityUtils.toString(httpEntity);

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        // return XML
        return xml;
    }
   
    /**
     * Getting XML DOM element
     * @param XML string
     * */
    public Document getDomElement(String xml)
    {   
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        try
        {
            DocumentBuilder db = dbf.newDocumentBuilder();
            InputSource is = new InputSource();
            is.setCharacterStream(new StringReader(xml));
                doc = db.parse(is);

            } catch (ParserConfigurationException e)
            {
                Log.e("Error: ", e.getMessage());
                return null;
            } catch (SAXException e)
            {
                Log.e("Error: ", e.getMessage());
                return null;
            } catch (IOException e)
            {
                Log.e("Error: ", e.getMessage());
                return null;
            }

            return doc;
    }
   
   
     public String getValue(Element item, String str)
     {       
            NodeList n = item.getElementsByTagName(str);       
            return this.getElementValue(n.item(0));
        }
   
     public final String getElementValue( Node elem ) {
         Node child;
         if( elem != null){
             if (elem.hasChildNodes()){
                 for( child = elem.getFirstChild(); child != null; child = child.getNextSibling() )
                 {
                     if( child.getNodeType() == Node.TEXT_NODE  )
                     {
                         return child.getNodeValue();
                     }
                 }
             }
         }
         return "";
     }
}