How Can get data from Sqlserver to android?

Question

I am trying to get data from SQL server to my android app. First I have connected my app with a web service built in C# like this:

public class DataHelper
{
    public static Cliente[] ListadoClientes()
    {
        DataSet dst = new DataSet();
        string instrumentos = "";
        /*try
        {*/
        var connectionString = 
            ConfigurationManager.ConnectionStrings["TestAndroid"].ConnectionString;
        //create string connections
        SqlConnection con = new SqlConnection(connectionString);
        //open connections
        con.Open();
        /* if (con != null)
        {*/
        //query to database
        SqlCommand cmd = new SqlCommand(
            "select clrut,Clnombre,Clcodigo from parametros..CLIENTE", con);
        SqlDataReader dr = cmd.ExecuteReader();
        List<Cliente> lista = new List<Cliente>();
        while (dr.Read())
        {
            lista.Add(new Cliente(dr.GetDecimal(0),
                dr.GetString(1),
                dr.GetDecimal(2)));
        }
        //dr.Close();
        con.Close();
        return lista.ToArray();
    }
}

That code is server-side and I'm capturing the data on android.

//Tarea Asíncrona para llamar al WS de consulta en segundo plano
private class TareaWSConsulta extends AsyncTask<String,Integer,Boolean> {
    private Cliente[] listaClientes;
    protected Boolean doInBackground(String... params) {
        boolean resul = true;
        final String NAMESPACE = "http://xxxx.net";
        final String URL="http://iplocaliis/ServicioClientes.asmx";
        final String METHOD_NAME = "metodoCliente";
        final String SOAP_ACTION ="http://xxxxxx/ListadoClientes";
        SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);
        SoapSerializationEnvelope envelope =
            new SoapSerializationEnvelope(SoapEnvelope.VER11);
        envelope.dotNet = true;
        envelope.setOutputSoapObject(request);
        HttpTransportSE transporte = new HttpTransportSE(URL);
        try {
            transporte.call(SOAP_ACTION, envelope);
            SoapObject resSoap =(SoapObject)envelope.getResponse();
            listaClientes = new Cliente[resSoap.getPropertyCount()];
            for (int i = 0; i < listaClientes.length; i++) {
                SoapObject ic = (SoapObject)resSoap.getProperty(i);
                Cliente cli = new Cliente();
                cli.id = Integer.parseInt(ic.getProperty(0).toString());
                cli.nombre = ic.getProperty(1).toString();
                cli.telefono = Integer.parseInt(ic.getProperty(2).toString());
                listaClientes[i] = cli;
            }
        } 
        catch (Exception e) 
        {
            resul = false;
        } 
        return resul;
    }
    protected void onPostExecute(Boolean result) {
        if (result) {
            //Rellenamos la lista con los nombres de los clientes
            final String[] datos = new String[listaClientes.length];
            for(int i=0; i<listaClientes.length; i++)
                datos[i] = listaClientes[i].nombre;
            ArrayAdapter<String> adaptador =
                new ArrayAdapter<String>(MainActivity.this,
                android.R.layout.simple_list_item_1, datos);
            lstClientes.setAdapter(adaptador);
        }
        else {
            txtResultado.setText("Error!");
        }
    }
}

It works good with Wi-Fi but when I change my connection to 3G it doesn't work. The web services are published in a local IIS.

Answer 1

这是一个网络问题，除非您配置路由器，否则您无法从公共 IP 地址访问本地 Web 服务。

Answer 2

There's no problem with your code, it's problem of networking.

1. Why it works with Wifi connected ?

When your server and phone both connected with a same WLAN, they both in a local network, so your app can access the server.

2. Why not 3G network ?

Once the phone connected with 3G network, then phone and server are not in a same network. In addition, your server IP is not a public IP, so your app can not access to your server.

3. How to make server accessible

• Apply a public IP for your server.
• Buy cloud server, and deploy your webservice on the server.