How can I pass value from Flutter App to PHP mysql query then return data from it?

I already tried this: A previous question

But it wont work! Nothing appears in the App! This is my flutter code to set Data .. num is equal to 1 so I can get the first user:

  Future setData() async {
      final response = await http.post(theUrl, body: {"id": num});
setResponse = json.decode(response.body);
return setResponse;
 }

and this is for getting theData Flutter Code:

    Future getMethod() async {
String theUrl = "http://192.168.8.53/flutter_test/phpConnect.php";
var res = await http
    .get(Uri.encodeFull(theUrl), headers: {"Accept": "application/json"});
responseBody = json.decode(res.body);
return responseBody;
 }

this is my php getData.php code:

<?php
require('connection.php');

$userId = $_POST['id'];

$makeQuery = "Select * From tableName Where id=" .$userId;
$statement = $connection->prepare($makeQuery);
$statement->execute();
$myarray = array();

while ($resulteFrom = $statement ->fetch()){

array_push(
$myarray,array(
"id"=>$resultFrom['id'],
"header"=>$resultFrom['header'],
"body"=>$resultFrom['body']
   )
  );
 }
echo json_encode($myarray);

?>

Thanx in Advance <3