How to Grab a URL Source with ProgressDialog and AsyncTask in android?

import java.io.IOException;

import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.Toast;
 
public class SimpleWebGrab extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
     
        grabURL("http://android.com");
    }
 
    public void grabURL(String url) {
        new GrabURL().execute(url);
    }
 
    private class GrabURL extends AsyncTask<String, Void, Void> {
        private final HttpClient Client = new DefaultHttpClient();
        private String Content;
        private String Error = null;
        private ProgressDialog Dialog = new ProgressDialog(SimpleWebGrab.this);
     
        protected void onPreExecute() {
            Dialog.setMessage("Downloading source..");
            Dialog.show();
        }

        protected Void doInBackground(String... urls) {
            try {
                HttpGet httpget = new HttpGet(urls[0]);
                ResponseHandler<String> responseHandler = new BasicResponseHandler();
                Content = Client.execute(httpget, responseHandler);
            } catch (ClientProtocolException e) {
                Error = e.getMessage();
                cancel(true);
            } catch (IOException e) {
                Error = e.getMessage();
                cancel(true);
            }
         
            return null;
        }
     
        protected void onPostExecute(Void unused) {
            Dialog.dismiss();
            if (Error != null) {
                Toast.makeText(SimpleWebGrab.this, Error, Toast.LENGTH_LONG).show();
            } else {
                Toast.makeText(SimpleWebGrab.this, "Source: " + Content, Toast.LENGTH_LONG).show();
            }
        }
     
    }
}