Unable to retrieve the value of textfield

Unable to retrieve the value of textfield

i am the newbee in Android Development. I had developed an app contains a
login, the credentials must be passed in the text field and later it will
call a webservice. I am facing the issue as user and password is not
getting copied at the required position. Please help me out.
package com.authorwjf.http_get;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class Main extends Activity implements OnClickListener {
EditText txtUserName;
EditText txtPassword;
@Override
public void onCreate(Bundle savedInstanceState) {
txtUserName=(EditText)this.findViewById(R.id.editText1);
txtPassword=(EditText)this.findViewById(R.id.editText2);
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findViewById(R.id.my_button).setOnClickListener(this);
}
@Override
public void onClick(View arg0) {
Button b = (Button)findViewById(R.id.my_button);
b.setClickable(false);
new LongRunningGetIO().execute();
}
private class LongRunningGetIO extends AsyncTask <Void, Void, String> {
protected String getASCIIContentFromEntity(HttpEntity entity)
throws IllegalStateException, IOException {
InputStream in = entity.getContent();
StringBuffer out = new StringBuffer();
int n = 1;
while (n>0) {
byte[] b = new byte[4096];
n = in.read(b);
if (n>0) out.append(new String(b, 0, n));
}
return out.toString();
}
@Override
protected String doInBackground(Void... params) {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
String user= txtUserName.getText().toString();
String pass= txtPassword.getText().toString();
System.out.println("USERRRR"+user);
System.out.println(pass);
//String user="at@ril.com";
//String pass= "123456";
String accessTokenQry = "{"+
"\"uid\":\""+user+"\","+
"\"password\":\""+pass+"\","+
"\"consumptionDeviceId\":\"fder-et3w-3adw2-2erf\","+
"\"consumptionDeviceName\":\"Samsung Tab\""+
"}";
HttpPost httpPost = new
HttpPost("http://devssg01.ril.com:8080/v2/dip/auth/login");
httpPost.setHeader("Content-Type",
"application/json");
httpPost.setHeader("X-API-Key",
"l7xx7914b8704b2d4b029ab9c4b1b9c66dbf");
StringEntity input;
try {
input = new StringEntity(accessTokenQry);
httpPost.setEntity(input);
} catch (UnsupportedEncodingException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
String text = null;
try {
HttpResponse response = httpClient.execute(httpPost,
localContext);
HttpEntity entity = response.getEntity();
text = getASCIIContentFromEntity(entity);
} catch (Exception e) {
return e.getLocalizedMessage();
}
return text;
}
protected void onPostExecute(String results) {
if (results!=null) {
EditText et = (EditText)findViewById(R.id.my_edit);
et.setText(results);
}
Button b = (Button)findViewById(R.id.my_button);
b.setClickable(true);
}
}
}