Whoever getting started to learn Web services - Android app interaction I hope this tutorial may be helpful, You can download the full source from here: https://github.com/harshadura/RDA-Android-ASP.WS-interact/archive/master.zip

Prerequisites: 
.NET framework, SQL server 2008, Android device/emulator
 
How to run.

1. Attach the MDF file into your SQL server.
2. Change the connection string at the C# project config according to your db connection.
3. Change the 'Web service URL' on the Android Application.

1. You will need to use WIFI tether to get connect your device with PC/otherwise you will need a router, both connected into it.
2. Sometimes you will need to configure the security restrictions of your IIS web server to get connect the device.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] 

public class Service : System.Web.Services.WebService
{
    public Service () {

        //Uncomment the following line if using designed components 
        //InitializeComponent(); 
    }

    [WebMethod]
    public String GetEmployeeByID(String id) {
          
            DataSet2TableAdapters.EmployeeTableAdapter dt1 = new DataSet2TableAdapters.EmployeeTableAdapter();
            String ename = "" + dt1.getEmpByID(id);
            return ename;
    }

    [WebMethod]
    public Employee[] GetEmployees()
    {
        var employees = new List();

        try
        {
            string connect = @"Data Source=HARSHADURA-AZUS\SQLEXPRESS;Initial Catalog=RDA;Integrated Security=True";
            string query = "SELECT eid, ename FROM Employee";

                SqlConnection thisConnection = new SqlConnection(connect);
                thisConnection.Open();
                SqlCommand thisCommand = thisConnection.CreateCommand();
                thisCommand.CommandText = query;
                SqlDataReader thisReader = thisCommand.ExecuteReader();
                while (thisReader.Read())
                {
                    var emp = new Employee();
                    emp.eid = thisReader["eid"].ToString();
                    emp.ename = thisReader["ename"].ToString();
                    employees.Add(emp);
                }
                thisReader.Close();
                thisConnection.Close();
            }
            catch (SqlException e)
            {
                Console.WriteLine(e.Message);
            }
        return employees.ToArray();
    }
}

 private SoapObject result = null;

 private static String SOAP_ACTION = "http://tempuri.org/GetEmployeeByID";
 private static String NAMESPACE = "http://tempuri.org/";
 private static String METHOD_NAME = "GetEmployeeByID";
 private static String URL = "http://192.168.123.100:8080/Service.asmx?WSDL";

 public void connectSOAP(String empid) {
  SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
  request.addProperty("id", empid);

  SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(
    SoapEnvelope.VER11);
  envelope.dotNet = true;
  envelope.setOutputSoapObject(request);
  HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);
  try {
   androidHttpTransport.call(SOAP_ACTION, envelope);
  } catch (Exception e) {
   e.printStackTrace();
  }

  result = (SoapObject) envelope.bodyIn;
  
 }