Android PostResponseAsyncTask cant get string from android - php

Question

I have this application where I use PHP and Mysql for my queries in android studio but when im using update its not working the php should give me the string of what the $result gives me but its not giving any its blank.
Here are my codes.
Android
HashMap postData = new HashMap();
if (TextUtils.isEmpty(etCarModel.getText().toString())) {
Toast.makeText(UpdateClick.this, "Car model is empty", Toast.LENGTH_SHORT).show();
return;
}
if (TextUtils.isEmpty(etCarType.getText().toString())) {
Toast.makeText(UpdateClick.this, "Car type is empty", Toast.LENGTH_SHORT).show();
return;
}
if (TextUtils.isEmpty(etCapacity.getText().toString())) {
Toast.makeText(UpdateClick.this, "Capacity is empty", Toast.LENGTH_SHORT).show();
return;
}
if (TextUtils.isEmpty(etPlateNumber.getText().toString())) {
Toast.makeText(UpdateClick.this, "Plate Number is empty", Toast.LENGTH_SHORT).show();
return;
}
if (TextUtils.isEmpty(etPrice.getText().toString())) {
Toast.makeText(UpdateClick.this, "Price is empty", Toast.LENGTH_SHORT).show();
return;
}
postData.put("txtCar_No", tvCar_No.getText().toString());
postData.put("txtCarModel", etCarModel.getText().toString());
postData.put("txtCarType", etCarType.getText().toString());
postData.put("txtCapacity", etCapacity.getText().toString());
postData.put("txtPlateNumber", etPlateNumber.getText().toString());
postData.put("txtCarPrice", etPrice.getText().toString());
postData.put("image", toString());
postData.put("txtFuelType", spFuelType.getSelectedItem().toString());
PostResponseAsyncTask taskUpdate = new PostResponseAsyncTask(UpdateClick.this, postData, new AsyncResponse() {
#Override
public void processFinish(String q) {
Log.d(TAG,q);
if(q.contains("success")){
Toast.makeText(UpdateClick.this, "Car details updated!", Toast.LENGTH_SHORT).show();
Intent in = new Intent(UpdateClick.this, OwnerTabs.class);
startActivity(in);
finish();
}else{
Toast.makeText(getApplicationContext(), "Error ? " + q.toString(), Toast.LENGTH_SHORT).show();
}
}
});
taskUpdate.execute("http://carkila.esy.es/update.php");
}
PHP
<?php
include_once("connection.php");
if(isset($_POST['txtCar_No']) && isset($_POST['txtCarModel']) &&
isset($_POST['txtCarType']) && isset($_POST['txtCapacity']) &&
isset($_POST['image']) && isset($_POST['txtFuelType']) &&
isset($_POST['txtPlateNumber']) && isset($_POST['txtcarPrice']))
{
$now = DateTime::createFromFormat('U.u', microtime(true));
$id = $now->format('YmdHis');
$upload_folder = "upload";
$path = "$upload_folder/$id.jpeg";
$fullpath = "http://carkila.esy.es/$path";
$image = $_POST['image'];
$Car_No = $_POST['txtCar_No'];
$Car_Model = $_POST['txtCarModel'];
$Car_Type = $_POST['txtCarType'];
$Capacity = $_POST['txtCapacity'];
$Fuel_Type = $_POST['txtFuelType'];
$PlateNumber = $_POST['txtPlateNumber'];
$carPrice = $_POST['carPrice'];
$query = "UPDATE tbl_cars SET Car_Model='$Car_Model', Car_Type='$Car_Type', Capacity='$Capacity', Image='$fullpath', fuelType='$Fuel_Type',carPlatenuNumber='$PlateNumber' ,carPrice= '$carPrice' WHERE 'Car_No'=$Car_No";
$result = mysqli_query($conn,$query);
$count = mysqli_affected_rows($conn);
if($result == TRUE && $count > 0){
echo "success";
exit();
}else{
print_r (mysqli_error($conn));
echo "failed";
exit();
}
}
?>

Answer 1

i am from mobile, but try to change $result:
$result = mysqli_query($conn,$query);
With this:
$result = mysqli_query($conn,$query) or die(mysqli_error($conn));
EDIT:
You have to check whether the information is sent, so try to insert it to your code:
$filename = "log.txt";
$fh = fopen($filename, "a") or die("Could not open log file.");
$post = var_dump($post);
fwrite($fh, date("d-m-Y, H:i")." - $post\n") or die("Could not write file!");
fclose($fh);
Dont forget to create a log.txt file with chmod 777