Error in php code.Maybe my for loop is wrong? - php

Question

ok i am not familiar with php but i have to use it for my android application to take data from mysql server.This is what i ve done so far.When i call this script from the app i want to create a new booking row and all the booked seat rows that the user selected . The above php throws an exception but i dont know where.
<?php
#open connection
require("config.inc.php");
//if posted data is not empty
if (!empty($_POST)) {
$query = "INSERT INTO booking (show_id) VALUES (:showId) ";
$query_params = array(
':showId' => $_POST['showId']);
$query_params1 = array(
':seatNo' => $_POST['seatNo']);
try {
$stmt = $db->prepare($query);
$result = $stmt->execute($query_params);
$lastRow = $db->lastInsertId('booking');
for($i=0; $i<$_POST['size']; $i++){
$query1 = "INSERT INTO booked_seats (booking_id,seat) VALUES ($lastRow,:seatNo) ";
$query_params1 = array(
':seatNo' => $_POST["seat{$i}"]);
$stmt = $db->prepare($query1);
$result = $stmt->execute($query_params1);
}
}
catch (PDOException $ex) {
$response["success"] = 0;
$response["message"] = "Database Error. Please Try Again!";
die(json_encode($response));
}
$response["success"] = 1;
$response["message"] = "Reservation Completed!";
echo json_encode($response);
}
?>
and this is the java code where i call the php
protected String doInBackground(String... strings) {
String msg=null;
try {
List<NameValuePair> params=new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("showId", showId));
params.add(new BasicNameValuePair("size",Integer.toString(selectedSeats.size())));
for(int i=0; i<selectedSeats.size(); i++) {
params.add(new BasicNameValuePair("seat"+Integer.toString(i),Integer.to String(selectedSeats.get(i))));
}
JSONObject jsonObject=jsonParser.makeHttpRequest( LOGIN_URL, "POST", params);
msg = jsonObject.getString(TAG_MESSAGE);
}
catch (JSONException e){
e.printStackTrace();
}
catch(Exception e){
e.printStackTrace();
}
return msg;
}
I know that the tag seat* that i use may be a little bit unusual but i couldnt think anything else.
The weird think is that the above code works.It makes the changes in the database but the msg
"Reservation Completed! is never reachable because it throws an exception somewhere!

Answer 1

Try using the following to echo the json:
header('Content-Type: application/json');
echo json_encode($response);
Also, ommit the PHP closing tag ?>. Last but not least; make sure nothing else is being sent to output before echo-ing your JSON.
Complete answer:
<?php
#open connection
require("config.inc.php");
//if posted data is not empty
if (!empty($_POST)) {
$query = "INSERT INTO booking (show_id) VALUES (:showId) ";
$query_params = array(
':showId' => $_POST['showId']);
try {
$stmt = $db->prepare($query);
$result = $stmt->execute($query_params);
$lastRow = $db->lastInsertId('booking');
for($i=0; $i<$_POST['size']; $i++){
$query1 = "INSERT INTO booked_seats (booking_id,seat) VALUES ($lastRow,:seatNo) ";
$query_params1 = array(
':seatNo' => $_POST["seat" . $i]);
$stmt = $db->prepare($query1);
$result = $stmt->execute($query_params1);
}
}
catch (PDOException $ex) {
$response["success"] = 0;
$response["message"] = "Database Error. Please Try Again!";
die(json_encode($response));
}
$response["success"] = 1;
$response["message"] = "Reservation Completed!";
header('Content-Type: application/json');
echo json_encode($response);
}