Android-在AsyncTask中获得空响应

Question

I wrote a XMLParser myself to get a certain string from a xml, everything works fine when testing it in a Java application, but when doing it in android it returns a null value. I researched and found out that I will need to use AsyncTask in order to call the web service in a separate thread. I did and I still get a null value. Here is the code

 private class AsyncTaskRunner extends AsyncTask<String, String, String> {

          private String resp;

          @Override
          protected String doInBackground(String... params) {
           //publishProgress("Sleeping..."); // Calls onProgressUpdate()
            XmlParser getP = new XmlParser();
            resp = getP.getClo();
           return resp;
          }
          @Override
          protected void onPostExecute(String result) {

           Log.d("Verify: ", "" + result);    
          }
}

I execute this by making an OnClick on a dialog interface : new AsyncTaskRunner().execute(); Thanks!

Answer 1

below piece of code obviously return null.

 XmlParser getP = new XmlParser();
        resp = getP.getClo();
       return resp;

since XmlParser getP = new XmlParser(); object creation happening, and your trying to access threr only with no value set that object

Answer 2

In your statement, XmlParser getP = new XmlParser(); you have only created an XmlParser, you have yet to set it to a value. It is effectively useless until you do something with it. for more information on the XmlParser see this documentation - http://groovy.codehaus.org/api/groovy/util/XmlParser.html