necesidad de un ejemplo de lesctura de webservice asincronico con ArrayList<HashMap<String, String>>

[Pepe Ballaga]

Holaa amigos deseo hacer una aplicacion que lea de un webservice de
manera asincronica datos de tipo ArrayList<HashMap<String, String>>..
he encontrado algunos ejemplos en internet, pero me dan error. Por
favor si tienes algun ejemplo completo te agradeceria me lo enviaras.
Saludos

PEPE

Este es mi ejemplo y me error en el momento de conectarse al
webservice...curioso pues si cambio el tipo de datos a
ArrayList<String> pues funciona perfectamente


public class MainActivity extends AppCompatActivity {

private String NAMESPACE, URL,METHOD_NAME, SOAP_ACTION ="";
SoapObject fila, filas;
//List<String> arraylist = new ArrayList<String>();
ArrayList<HashMap<String, String>> list;
public static final String FIRST_COLUMN="First";
public static final String SECOND_COLUMN="Second";
public static final String THIRD_COLUMN="Third";
public static final String FOURTH_COLUMN="Fourth";
//private ArrayList<HashMap> list;
//ArrayList<HashMap> arraylist ;

ArrayAdapter<String> arrayadapter;


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);


NAMESPACE = Helper.getConfigValue(this,"NAMESPACE");
URL = Helper.getConfigValue(this, "URL");
METHOD_NAME = "Unidades";
SOAP_ACTION = NAMESPACE+METHOD_NAME;
//SOAP_ACTION = URL+METHOD_NAME;
filas=null;

String URL="";
Dowork task = new Dowork();
ArrayList<HashMap<String, String>> arr; // = new
ArrayList<HashMap<String, String>>();
task.execute();

ListView listView=(ListView)findViewById(R.id.listView1);

}



public class Dowork extends AsyncTask<String, Void,
ArrayList<HashMap<String, String>>> {

private final ProgressDialog dialogue = new
ProgressDialog(MainActivity.this);

@Override
protected void onPreExecute() {
this.dialogue.setMessage("Conectando...");
this.dialogue.show();
}

@Override
protected void onCancelled() {
super.onCancelled();
}

@Override
protected void onPostExecute( ArrayList<HashMap<String,
String>> listica) {

ListView listView=(ListView)findViewById(R.id.listView1);
//aca debo obtener el arreglo devuelto
if (listica.isEmpty() )
{


}
if (this.dialogue.isShowing()) {

this.dialogue.dismiss();
}

}


@Override
protected ArrayList<HashMap<String,String>>
doInBackground(String ...params) {

SoapObject request = new SoapObject(URL, METHOD_NAME);


SoapObject obj, obj1;

ArrayList<HashMap<String,String>> listica=new
ArrayList<HashMap<String,String>>();

SoapSerializationEnvelope envelope = new
SoapSerializationEnvelope(SoapEnvelope.VER11);
envelope.dotNet=true;
envelope.setOutputSoapObject(request);
try
{
//aca me da error y se va
AndroidHttpTransport aht=new AndroidHttpTransport(URL);
aht.call(SOAP_ACTION,envelope);


obj1 = (SoapObject) envelope.bodyIn;

SoapObject obj2 =(SoapObject) obj1.getProperty(0);


obj = (SoapObject) envelope.getResponse();
obj1 = (SoapObject) obj.getProperty("diffgram");
filas = (SoapObject) obj1.getProperty("NewDataSet");

for (int i = 0; i < filas.getPropertyCount(); i++) {
fila = (SoapObject) filas.getProperty(i);
fila.getProperty(0).toString();// value of column 1
fila.getProperty(1).toString();// value of column 2

HashMap<String,String> hashmap=new HashMap<String,
String>();
hashmap.put(FIRST_COLUMN,fila.getProperty(1).toString());;
hashmap.put( SECOND_COLUMN,fila.getProperty(2).toString());;
hashmap.put(THIRD_COLUMN,fila.getProperty(3).toString());;
hashmap.put(FOURTH_COLUMN,fila.getProperty(4).toString());;

listica.add(hashmap);

}

return listica;

}
catch (Exception ex)
{
ex.printStackTrace();
}

return listica ;
}

}

}