Tutorial :- How to implement reusable Asyntask in android

How to implement reusable Asyntask in Android  :-
What is AsyncTask?  
Answer :-
AsyncTask enables proper and easy use of the UI thread. This class allows to perform background operations and publish results on the UI thread without having to manipulate threads and/or handlers.
AsyncTask is designed to be a helper class around Thread and Handler and does not constitute a generic threading framework. AsyncTasks should ideally be used for short operations (a few seconds at the most.) If you need to keep threads running for long periods of time, it is highly recommended you use the various APIs provided by the java.util.concurrent pacakge such as Executor, ThreadPoolExecutor and FutureTask.

/**
 * Activites that wish to be notified about results
 * in onPostExecute of an AsyncTask must implement
 * this interface.
 *
 * This is the basic Observer pattern.
 */
public interface ResultsListener {
    public void onResultsSucceeded(String result);
}

package com.example;

import java.io.IOException;

import org.ksoap2.SoapEnvelope;
import org.ksoap2.SoapFault;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapPrimitive;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
import org.xmlpull.v1.XmlPullParserException;

import android.os.AsyncTask;

public class MyAsyncTask extends AsyncTask<Void, Void, String> {

    ResultsListener listener;

    private static final String SOAP_ACTION = "http://tempuri.org/name";
    private static final String METHOD_NAME = "name";
    private static final String NAMESPACE = "http://tempuri.org/";
    public static String URL = "url";
    private SoapPrimitive resultsRequestSOAP = null;

    public void setOnResultsListener(ResultsListener listener) {
        this.listener = listener;
    }

    @Override
    protected String doInBackground(Void... voids) {
        String someString = "foo bar";
        String results = null;
        SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
        // SoapObject
        request.addProperty("address", "shivaji nagar pune");
        request.addProperty("mile", "20");
        SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(
                SoapEnvelope.VER11);
        envelope.dotNet = true;
        envelope.setOutputSoapObject(request);
        HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);

        try {
            androidHttpTransport.call(SOAP_ACTION, envelope);
            resultsRequestSOAP = (SoapPrimitive) envelope.getResponse();
            results = resultsRequestSOAP.toString();
        } catch (SoapFault e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (XmlPullParserException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return results;

    }

    @Override
    protected void onPostExecute(String result) {
        listener.onResultsSucceeded(result);

    }

}

MyAsyncTask task = new MyAsyncTask();
        /**
         * Set this Activity as the listener on the AsyncTask. The AsyncTask
         * will now have a refence to this Activity and will call
         * onResultsSucceeded() in its onPostExecute method.
         */
        task.setOnResultsListener(this);