Have Android App communicate to PHP file. : I'm trying to have my android app communicate with my friends php file which stores data into our database and then registers that data for a new user account.  I am new to PHP but I can read it.  But whatever I try, nothing seems to be able to be passing the values through to his post requests.  Ive tried everything from Volley Requests to JSON Parsing and I cant get it to work.  

Here is his PHP file.

    enter code here
    <?php 
    ini_set('display_errors', 1);
    header('Content-type: text/html; charset=utf-8');
    //$user = (int)$_POST['user_id'];
    $email = $_POST['email'];
    $password1 = $_POST['psw'];
    $password2 = $_POST['psw-repeat'];
    $first = $_POST['first_name']; 
    $last = $_POST['last_name']; 

    //<input type="checkbox" checked="checked"> Remember me

    include 'connRW.php';

    $stmt = $connRW->prepare("SELECT * FROM AdUsers WHERE email = :email or 
    fb_email 
    = :fb_email");
    $stmt->bindValue(':email', $email);
    $stmt->bindValue(':fb_email', $email);
    $stmt->execute();

    $row1 = $stmt->fetch(PDO::FETCH_ASSOC);

    $stmt = $connRW->prepare("SELECT * FROM AdPublishers WHERE email = :email or 
    fb_email = :fb_email");
    $stmt->bindValue(':email', $email);
    $stmt->bindValue(':fb_email', $email);
    $stmt->execute();

    $row2 = $stmt->fetch(PDO::FETCH_ASSOC);

    if (!$row1 && !$row2 && $password1)
    {
	if ($password1 == $password2) {
		$pwsaltedhashed = password_hash($password1, PASSWORD_DEFAULT);

		$stmt = $connRW->prepare("SELECT raadz_user_id FROM GetNext");
		$stmt->execute();
		
		$row = $stmt->fetch(PDO::FETCH_ASSOC);
		$next_user_id = $row["raadz_user_id"] + 1;

		$stmt = $connRW->prepare("UPDATE GetNext SET raadz_user_id = 
    :next_user_id");
		$stmt->bindValue(':next_user_id', $next_user_id, PDO::PARAM_INT);
		$stmt->execute();
		
		$stmt = $connRW->prepare("INSERT INTO AdUsers ( raadz_user_id, email, 
    password, first_name, last_name )
				 VALUES ( :user_id, :email, :password, :first_name, :last_name 
    )");
		$stmt->bindValue(':user_id', $next_user_id, PDO::PARAM_INT);
		$stmt->bindValue(':email', $email);
		$stmt->bindValue(':password', $pwsaltedhashed);
		$stmt->bindValue(':first_name', $first);
		$stmt->bindValue(':last_name', $last);
		$stmt->execute();
		
		$confirm_string = $next_user_id . substr($first, 0, 2) . substr($last, 
    0, 2);








And this is my Java class in Android Studio I'm using:

    enter code here
    public class RegisterActivity extends AppCompatActivity {

    TextView tvLogin;
    Button bRegister;
    EditText etEmail;
    EditText etPassword;
    EditText etPasswordRepeat;
    EditText etfirstName;
    EditText etlastName;
    String url = "https://example.com/usersignup.php";
    String gEmail;
    String gPassword;
    String gPasswordRepeat;
    String gFirst;
    String gLast;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        etEmail = (EditText) findViewById(R.id.etEmail);
        etPassword = (EditText) findViewById(R.id.etPassword);
        etPasswordRepeat = (EditText) findViewById(R.id.etPasswordRepeat);
        etfirstName = (EditText) findViewById(R.id.firstName);
        etlastName = (EditText) findViewById(R.id.lastName);
        tvLogin = (TextView) findViewById(R.id.tvLogin);
        bRegister = (Button) findViewById(R.id.bRegister);
        gEmail = etEmail.getText().toString();
        gPassword = etPassword.getText().toString();
        gPasswordRepeat = etPasswordRepeat.getText().toString();
        gFirst = etfirstName.getText().toString();
        gLast = etlastName.getText().toString();


        tvLogin.setOnClickListener(new View.OnClickListener()

        {
            public void onClick(View v) {
                Intent intent = new Intent(v.getContext(), MainActivity.class);
                startActivity(intent);
            }
        });

        bRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                String url = "https://raadz.com/usersignup.php";
                StringRequest MyStringRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        if(response.contains("Message could not be send.")) {
                            Toast.makeText(getApplicationContext(), "Message not sent", Toast.LENGTH_SHORT).show();
                        }
                        if(response.contains("Message has been sent")){
                            Toast.makeText(getApplicationContext(), "Message sent", Toast.LENGTH_SHORT).show();
                        }
                        //This code is executed if the server responds, whether or not the response contains data.
                        //The String 'response' contains the server's response.
                    }
                }, new Response.ErrorListener() { //Create an error listener to handle errors appropriately.
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(getApplicationContext(), "Error", Toast.LENGTH_SHORT).show();
                        //This code is executed if there is an error.
                    }
                }) {
                    protected Map<String, String> getParams() {
                        Map<String, String> MyData = new HashMap<String, String>();
                        MyData.put("email", gEmail);
                        MyData.put("psw", gPassword);
                        MyData.put("psw-repeat", gPasswordRepeat);
                        MyData.put("first_name", gFirst);
                        MyData.put("last_name", gLast);

                        return MyData;
                    }
                };
  
  
  
    MySingleton.getInstance(getAppContext()).addToRequestQueue(MyStringRequest);
            }
        });
    }
    }

What am I doing wrong?