How can use I use PHP as back-end for ionic framew

Can anyone give an example of using php at the backend with Angular JS at the front-end in the Ionic Framework?

Of Course !

Me and my partner just completed working on a IONIC App integrated with PHP as its backend.

Just like a regular Frontend-backend, requests and responses are in the form of JSON.

For getting started quickly, here is a sample code we built for ourselves :

send.php

<?php
// Prevent caching.
//header('Cache-Control: no-cache, must-revalidate');

// The JSON standard MIME header.
//header('Content-type: application/json');          

$data = array(
    "username" => "one",
    "email" => "ifyoucanreadthis@yes.com",
    "age"  => 22
    );

// Send the data.
echo json_encode($data);
?>

recieve.php

<?php

 /*
   * Collect all Details from Angular HTTP Request.
   */
    $postdata = file_get_contents("php://input");
    $request = json_decode($postdata);
    $usr = $request->email;
    $pass = $request->pass;

    echo "<h1> Username is : " . $usr . "<br /> and password is : ". $pass."</h1>"; //this will go back under "data" of angular call.
    /*
     * You can use $email and $pass for further work. Such as Database calls.
    */    

?>

Hope this helps you !

EDIT 1 :

The benefits of using PDO is over-rated. Read more about it here : http://code.tutsplus.com/tutorials/pdo-vs-mysqli-which-should-you-use--net-24059

I am assuming that you know about basic code for connecting to a database (http://www.w3schools.com/php/php_mysql_intro.asp).

<?php
$servername = "localhost";
$username = "username";
$password = "password";

// Create connection
$conn = new mysqli($servername, $username, $password);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
echo "Connected successfully";
?>

As far as Angular coding is concerned, you may find the following links useful (sorry I don't have the angular code on this machine) :

http://codeforgeek.com/2014/07/angular-post-request-php/

http://www.cleverweb.nl/javascript/a-simple-search-with-angularjs-and-php/

http://serebrov.github.io/html/2013-05-24-angular-post-to-php.html