Eu sucesso mostrar meus dados de serviço web JSON em listview, mas eu quero adicionar Asyntask .. Onde eu posso colocar o código Asyntask no meu código ..

Este meu código para mostrar dados na exibição de lista

public class Jadwal_remix extends ListActivity {
String v_date;
JSONArray r_js = null;
ArrayList<HashMap<String, String>> myArray = new ArrayList<HashMap<String,String>>();
public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.main);





    String status ="";
    String date = "";
    String result = "";
    String url = "http://10.0.2.2/remix/view_list.php";
    JSONParser jParser = new JSONParser();
    JSONObject json = jParser.AmbilJson(url);
    try
    {
        r_js = json.getJSONArray("view_list");

        for (int i =0; i < r_js.length(); i++)
        {
            String my_array = "";
            JSONObject ar = r_js.getJSONObject(i);
            status = ar.getString("st");
            date = ar.getString("date");
            result = ar.getString("result");

            if (status.trim().equals("er"))
            {
                my_array += "Sorry "+result;
                HashMap<String, String> map = new HashMap<String, String>();
                map.put("result", my_array);
                myArray.add(map);
            }
            else
            {
                my_array += "Date : "+date+" "+"Result : "+result;
                HashMap<String, String> map = new HashMap<String, String>();
                map.put("result", my_array);
                myArray.add(map);
            }

        }
    }
    catch (JSONException e) 
    {
         e.printStackTrace();
    }
    adapter_listview();

}

public void adapter_listview() {

    ListAdapter adapter = new SimpleAdapter(this, jadwalRemix,R.layout.my_list,new String[] { "result"}, new int[] {R.id.txtResult});
    setListAdapter(adapter);
}
}

E este JSONParser

public class JSONParser {

static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {

}

public JSONObject AmbilJson(String url) {

    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);

        HttpResponse httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity = httpResponse.getEntity();
        is = httpEntity.getContent();           

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;

}
 }

Por favor me ajude, onde eu posso colocar o código para Asyntask .. Muito obrigado ..

Ok, eu recebo código de amostra e meu código agora

public class Jadwal_remix extends ListActivity {
String v_date;
JSONArray r_js = null;
ArrayList<HashMap<String, String>> myArray = new ArrayList<HashMap<String,String>>();
public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.main);

private class myProses extends AsyncTask<Void, Void, Void> {
    ProgressDialog dialog;

    protected void onPreExecute() {
        dialog = ProgressDialog.show(Jadwal_remix.this, "", "Loading... Please wait", true);

    }
protected Void doInBackground(Void... params) {



    String status ="";
    String date = "";
    String result = "";
    String url = "http://10.0.2.2/remix/view_list.php";
    JSONParser jParser = new JSONParser();
    JSONObject json = jParser.AmbilJson(url);
    try
    {
        r_js = json.getJSONArray("view_list");

        for (int i =0; i < r_js.length(); i++)
        {
            String my_array = "";
            JSONObject ar = r_js.getJSONObject(i);
            status = ar.getString("st");
            date = ar.getString("date");
            result = ar.getString("result");

            if (status.trim().equals("er"))
            {
                my_array += "Sorry "+result;
                HashMap<String, String> map = new HashMap<String, String>();
                map.put("result", my_array);
                myArray.add(map);
            }
            else
            {
                my_array += "Date : "+date+" "+"Result : "+result;
                HashMap<String, String> map = new HashMap<String, String>();
                map.put("result", my_array);
                myArray.add(map);
            }

        }
    }
    catch (JSONException e) 
    {
         e.printStackTrace();
    }
    return null;
protected void onPostExecute(Void unused) {
        adapter_listview();
        dialog.dismiss();
    }

}

public void adapter_listview() {

    ListAdapter adapter = new SimpleAdapter(this, jadwalRemix,R.layout.my_list,new String[] { "result"}, new int[] {R.id.txtResult});
    setListAdapter(adapter);
}
}

Im get problema quando o servidor é morrer, ele ainda está carregando .. como eu posso mostrar mensagem ex: não pode se conectar ao servidor ..?