مشکل در ارسال مقادیر به سرور با volle y

سلام دوستان

لطفا اگه میشه نحوه ارسال مقادیر رو به سرور از طریق کتابخانه volly و نحوه اضافه کردن اون ها به دیتابیس رو توضیحی بدید....

این کد اندروید:

String tag_json_array = "tag_json_array";

String urlInsert = "http://192.168.8.100/bank-server/services.php?action=insert";

JSONObject jsonObject;

TextView txtUser;




@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.form_main);


  insertDataToServer();


}

private void insertDataToServer(){


  JsonArrayRequest jsonArrReq = new JsonArrayRequest(urlInsert,
    new Response.Listener<JSONArray>() {
      @Override
      public void onResponse(JSONArray jsonArray) {



      }
    },
    new Response.ErrorListener() {
      @Override
      public void onErrorResponse(VolleyError volleyError) {
        VolleyLog.e("TEST", volleyError.getMessage());
      }
    }){

    @Override
    protected Map<String, String> getParams() throws AuthFailureError {
      Map<String, String> params = new HashMap<String, String>();
      params.put("name", "Android-hive");
      params.put("email", "abc@androidhive.info");
      params.put("pass", "password123");
      params.put("balance", "10");
      return params;
    }


  };

  G.getInstance().addToRequestQueue(jsonArrReq, tag_json_array);


}

این هم کد سمت سرور:

<?php

if (isset($_REQUEST['action'])){
    $action = $_REQUEST['action'];
} else {
    echo "Invalid Data";
    exit;
}

if ($action=="read"){
    read();
} else if ($action=="insert"){
    insert();
} else if ($action=="update"){
    update();
} else if ($action=="remove"){
    remove();
}

/**
 *
 */
function connectToDatabase(){
    $connection=mysqli_connect("localhost", "root", "", "bank_db");

    if (mysqli_connect_errno()) {

        echo "Failed to connect to MySQL: " . mysqli_connect_error();
    }

    return $connection;
}

/**
 *
 */
function read(){

    $connection = connectToDatabase();
    $result = mysqli_query($connection, "SELECT * FROM user");

    $output = array();
    while($row = mysqli_fetch_array($result)) {
        $record = array();

        $record['user_id'] = $row['user_id'];
        $record['user_name'] = $row['user_name'];
        $record['user_email'] = $row['user_email'];
        $record['user_pass'] = $row['user_pass'];
        $record['user_balance'] = $row['user_balance'];

        $output[] = $record;
    }

    echo json_encode($output);
    mysqli_close($connection);
}

/**
 *
 */
function insert(){

    $connection = connectToDatabase();

    $name = $_REQUEST['name'];
    $email = $_REQUEST['email'];
    $pass = $_REQUEST['pass'];
    $balance = $_REQUEST['balance'];


    mysqli_query($connection, "INSERT INTO user VALUES (0, '$name', '$email', $pass' , '$balance)");

    mysqli_close($connection);
}

/**
 *
 */
function update(){
    $connection = connectToDatabase();

    $id = $_REQUEST['id'];
    $name = $_REQUEST['name'];
    $email = $_REQUEST['email'];
    $pass = $_REQUEST['pass'];
    $balance = $_REQUEST['balance'];
    mysqli_query($connection, "UPDATE user SET user_name=$name, user_email='$email', user_pass='$pass' , user_balance='$balance' WHERE user_id=$id");

    mysqli_close($connection);
}

/**
 *
 */
function remove(){
    $connection = connectToDatabase();

    $id = $_REQUEST['id'];
    mysqli_query($connection, "DELETE FROM user WHERE user_id=$id");

    mysqli_close($connection);
}

ممنون :)