namespace Stocktake {/// <summary>/// Summary description for RecordService/// </summary>
    [WebService(Namespace = "http://xxx.com/")][WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)][System.ComponentModel.ToolboxItem(false)]// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
    [System.Web.Script.Services.ScriptService]public class RecordService : System.Web.Services.WebService {[WebMethod][ScriptMethod(ResponseFormat = ResponseFormat.Json)]public StocktakeCode getStocktakeCode() {var result = new StocktakeCode() {Code = "Testing",Remark = "Some Remark"};return result;}}public class StocktakeCode {public string Code {get;set;}public string Remark {get;set;}}
}

public class DataAccess {  public static String getStocktakeCode(StocktakeActivity activity)throws IOException {HttpHost target = new HttpHost(getHostName(activity), getServerPort(activity));HttpClient client = new DefaultHttpClient();HttpPost post = new HttpPost(getStockCodeWsPath(activity));post.addHeader("Content-type", "application/json; charset=utf-8"); //  THIS IS IMPORTANT
    HttpEntity results = null;try{HttpResponse response=client.execute(target, post);results = response.getEntity();return EntityUtils.toString(results);} catch (Exception e){throw new IOException("Web Service failed.");} finally{if(results!=null){try{results.consumeContent();} catch (IOException e){}}}}
}

<webServices><protocols><add name="HttpPost"/></protocols>
</webServices>

JSONObject raw = new JSONObject(HttpPost_result);
String text = raw.getString("d");

JSONObject raw = new JSONObject(HttpPost_result);
if(!raw.isNull("d")){String text = raw.getString("d");JSONObject newObj = new JSONObject(text);TextView tv = (TextView)activity.findViewById(R.id.textViewStocktakeCode);tv.setText(newObj.getString("Code"));TextView tv2 = (TextView)activity.findViewById(R.id.textViewStocktakeRemark);tv2.setText(newObj.getString("Remark"));activity.setIsStocktakeAllowed(true);
} else {//...
}

String result = new StocktakeCodeWorker(StocktakeActivity.this).doInBackground((String[])null);

new StocktakeCodeWorker(StocktakeActivity.this).execute((String[])null);

Intent intent = new Intent("com.google.zxing.client.android.SCAN");
intent.setPackage("com.google.zxing.client.android"); // THIS IS IMPORTANT
intent.putExtra("SCAN_MODE","ONE_D_MODE");
intent.putExtra("SCAN_FORMAT", "CODE_128");
startActivityForResult(intent, SCAN_BARCODE_REQUEST);

<EditTextPreferenceandroid:key="server_port"android:title="@string/preference_serverPort"android:summary="@string/preference_serverPortRemark"android:dialogTitle="@string/preference_serverPort"  android:inputType="number"android:defaultValue="80" />

public static int getServerPort(StocktakeActivity activity){SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(activity);String textResult = sp.getString("server_port", "80").trim();return Integer.parseInt(textResult);
}

<uses-permission android:name="android.permission.INTERNET"/>