Salve,
ho creato un semplice webservice che fa la somma di due numeri e un'app di prova su android che utilizza il webservice.

Il codice del webservice è il seguente:

INTERFACCIA:
codice:
package com.example;

import javax.jws.WebService;

@WebService
public interface Somma {
	public int returnSomma(int a, int b);
}
CLASSE JAVA:
codice:
package com.example;

import javax.jws.WebService;

@WebService
public class SommaImpl implements Somma {

	public int returnSomma(int a, int b)
	{
		return a+b;
	}
}
Ho deployato il webservice su jboss e il wsdl ottenuto è il seguente:
codice:
<wsdl:definitions name="SommaImplService" targetNamespace="http://example.com/" xmlns:ns1="http://schemas.xmlsoap.org/soap/http" xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:tns="http://example.com/" xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <wsdl:types>
<xs:schema elementFormDefault="unqualified" targetNamespace="http://example.com/" version="1.0" xmlns:tns="http://example.com/" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="returnSomma" type="tns:returnSomma"/>
<xs:element name="returnSommaResponse" type="tns:returnSommaResponse"/>
<xs:complexType name="returnSomma">
    <xs:sequence>
      <xs:element name="arg0" type="xs:int"/>
      <xs:element name="arg1" type="xs:int"/>
    </xs:sequence>
  </xs:complexType>
<xs:complexType name="returnSommaResponse">
    <xs:sequence>
      <xs:element name="return" type="xs:int"/>
    </xs:sequence>
  </xs:complexType>
</xs:schema>
  </wsdl:types>
  <wsdl:message name="returnSomma">
    <wsdl:part element="tns:returnSomma" name="parameters">
    </wsdl:part>
  </wsdl:message>
  <wsdl:message name="returnSommaResponse">
    <wsdl:part element="tns:returnSommaResponse" name="parameters">
    </wsdl:part>
  </wsdl:message>
  <wsdl:portType name="Somma">
    <wsdl:operation name="returnSomma">
      <wsdl:input message="tns:returnSomma" name="returnSomma">
    </wsdl:input>
      <wsdl:output message="tns:returnSommaResponse" name="returnSommaResponse">
    </wsdl:output>
    </wsdl:operation>
  </wsdl:portType>
  <wsdl:binding name="SommaImplServiceSoapBinding" type="tns:Somma">
    <soap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/>
    <wsdl:operation name="returnSomma">
      <soap:operation soapAction="" style="document"/>
      <wsdl:input name="returnSomma">
        <soap:body use="literal"/>
      </wsdl:input>
      <wsdl:output name="returnSommaResponse">
        <soap:body use="literal"/>
      </wsdl:output>
    </wsdl:operation>
  </wsdl:binding>
  <wsdl:service name="SommaImplService">
    <wsdl:port binding="tns:SommaImplServiceSoapBinding" name="SommaImplPort">
      <soap:address location="http://RC530:8080/SommaWS-Maven/SommaImpl"/>
    </wsdl:port>
  </wsdl:service>
</wsdl:definitions>
Infine ho creato la seguente activity per android che permette di inserire due numeri ed eseguire la somma richiamando il webservice:
codice:
package com.example;

import org.ksoap2.SoapEnvelope;
import org.ksoap2.SoapFault;
import org.ksoap2.serialization.SoapObject;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.ksoap2.transport.HttpTransportSE;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
	private static String NAMESPACE = "http://example.com/";
	private static String METHOD_NAME = "returnSomma";
	private static String SOAP_ACTION = "";
	private static String URL = "http://192.168.1.68:8080/SommaWS-Maven/SommaImpl?wsdl";
	EditText editTextnumero1, editTextnumero2;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		editTextnumero1=(EditText)findViewById(R.id.editTextNumero1);
		editTextnumero2=(EditText)findViewById(R.id.editTextNumero2);
		
		Button buttonSomma=(Button)findViewById(R.id.buttonSomma);

		buttonSomma.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				chiamaWebServiceSomma();
			}
		});
	}
	
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	public void chiamaWebServiceSomma()
	{
		int numero1=Integer.parseInt(editTextnumero1.getText().toString());
		int numero2=Integer.parseInt(editTextnumero2.getText().toString());
		TextView textViewRisultato=(TextView)findViewById(R.id.textViewRisultato);
				
		SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);  
		request.addProperty("arg0", numero1);
		request.addProperty("arg1", numero2);

		SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
		envelope.setOutputSoapObject(request);
		envelope.dotNet = true;
		try {
			HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);
			
			//this is the actual part that will call the webservice
			androidHttpTransport.call(SOAP_ACTION, envelope);

			//Get the SoapFault from the envelope body.
			SoapFault error = (SoapFault)envelope.bodyIn;
			System.out.println("Error message : "+error.toString());
			
			//Get the SoapResult from the envelope body.
			SoapObject result = (SoapObject)envelope.bodyIn;

			if(result != null)
				//Get the first property and change the label text
				textViewRisultato.setText(result.getProperty(0).toString());
			else
				textViewRisultato.setText("Nessun risultato");
		} catch (Exception e) {
			textViewRisultato.setText("Eccezione!");
			e.printStackTrace();
		}
	}
}
Il problema è che quando avvio l'app ho il seguente messaggio di errore:
codice:
Error message : SoapFault - faultcode: 'soap:Client' faultstring: 'Unmarshalling Error: unexpected element (uri:"http://example.com/", local:"arg0"). Expected elements are <{}arg1>,<{}arg0> ' faultactor: 'null' detail: null
codice:
java.lang.ClassCastException: org.ksoap2.SoapFault cannot be cast to org.ksoap2.serialization.SoapObject
at com.example.MainActivity.chiamaWebServiceSomma(MainActivity.java:94)
at com.example.MainActivity$1.onClick(MainActivity.java:43)
at android.view.View.performClick(View.java:4211)
at android.view.View$PerformClick.run(View.java:17267)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4898)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
at dalvik.system.NativeStart.main(Native Method)