PhP Handle ArrayList send from android app

Hi I have send and arrayList eventIDBeacon using volley library. I want to ask how to decode the array and store in PhP array variable

Here is my code at android app

private void getEventDetailRespond(RequestQueue requestQueue) {
        eventDetail = new ArrayList<>();

        Map<String, Object> jsonParams = new ArrayMap<>();
        jsonParams.put(Config.EVENT_ID, eventIDBeacon);

        //Creating a JSONObject request
        JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST,Config.DATA_URL, new JSONObject(jsonParams),
                new Response.Listener<JSONObject>() {
                        @Override
                        public void onResponse(JSONObject respond) {
                            try {
                                Toast.makeText(Beacon_MainActivity.this,"eventDetail respond "+respond.toString(),Toast.LENGTH_LONG).show();
                                eventArray = new JSONArray();

                                eventArray = respond.getJSONArray("result");
                                getEventDetail(eventArray);

                            } catch (JSONException e) {
                                e.printStackTrace();
                            }

                        }
                    },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(Beacon_MainActivity.this, "Unable to fetch data event Detail: " +error.getMessage(),Toast.LENGTH_LONG).show();
                    }
                });

        //Adding request to the queue
        requestQueue.add(jsonObjectRequest);
    }

Here is my PHP server but seem not to work. how to handle ArrayList at server side? im still stuck with this. I want to get back the array and use SQL query to query value in the array and return the result send back to the android app?

<?php

if($_SERVER['REQUEST_METHOD']=='POST'){

// decoding the json array
$post = json_decode(file_get_contents("php://input"), true);

$eventID = $post['EventID'];

require_once('dbconnect.php');

$sql = "SELECT EventID, EventTitle, EventDesc, EventTime FROM Event WHERE EVENTID = '$eventID'";

$res = mysqli_query($con,$sql);

$result = array();


 while ($row = mysqli_fetch_array($res)){
        array_push($result,array(
            'EventID'=>$row['EventID'],
            'EventTitle'=>$row['EventTitle'],
            'EventDesc'=>$row['EventDesc'],
            'EventTime'=>$row['EventTime']
        ));
    }

    header('Content-Type: application/json');
    echo json_encode(array('result'=>$result), 256);    
    mysqli_close($con);
}

Any help should be much appreciate