How to get the rowcount from php file in android - php

Question

I'm comparing the username and password from the user input to the database data, and I used count to check if it is equal to 1 or 0.
If it's equal to 1, the editText should be set to 1, and if it's 0 it should be set to 0.
My problem is, it's always set to 0 even if the username and password is correct.
here is the name value pair and connection to the database:
username = etlogUsername.getText().toString();
password = etlogPassword.getText().toString();
String output = "";
//setting the NameValuePair
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
//adding the string variables inside the nameValuePairs
nameValuePairs.add(new BasicNameValuePair("user_username", username));
nameValuePairs.add(new BasicNameValuePair("user_password", password));
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://thesis-account.byethost7.com/workout_select_username.php");
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
//getting the response
HttpResponse response = httpclient.execute(httppost);
//setting up the entity
HttpEntity entity = response.getEntity();
is = entity.getContent();
here is the json that will read the data:
JSONArray jArray= new JSONArray(output);
for(int i = 0; i <jArray.length() ; i++){
JSONObject json = jArray.getJSONObject(i);
COUNT_user_id = json.getInt("num_rows");
if(COUNT_user_id == 1)
{
isEqual = true;
}
}
etlogUsername.setText(COUNT_user_id+"");
and here is the php file:
$sql = mysql_query("SELECT COUNT(user_id) AS num_rows FROM tbl_users
WHERE user_username='{ $username}' && user_password = '{$password}' ");
while($row=mysql_fetch_assoc($sql))
{
$output[]=$row;
}
print(json_encode($output));
mysql_close($con);