Java Android OutputStreamWriter write() not passing parameters to php file-Exceptionshub

I’m very new to android programming and I have a problem with OutputStreamWriter. Now, I’m working on a simple test application to send POST requests to a server. There is a PHP application on the server-side, which is designed to write data in a MYSQL database. When I run my android app it accesses the PHP file correctly but the parameters are not passed.

I have been conductive an extensive search over all types of forums and tried some of the answers given, but nothing worked for me. What am I doing wrong?

PHP

<?$conecta = mysqli_connect('localhost','username','password','killerbees');
if (!$conecta) {echo "Unable to verify nickname. Please, try again later!";}
else
{
    $sql = "SELECT * FROM KillerBees WHERE nickname = '" . addslashes($_POST['kbfnickname']) . "'";                                                                    
    if ($resultado = mysqli_query($conecta,$sql))
    {
        if (mysqli_num_rows($resultado) == 0)
        {       
            $sql = "INSERT INTO KillerBees (nickname, password, level, seconds) VALUES ('" . addslashes($_POST['kbfnickname']) . "', '" . addslashes($_POST['kbfpassword']) . "', 0, 0)";
                   $resultado = mysqli_query($conecta,$sql);
                   $_SESSION['nickname'] = $_POST['kbfnickname'];
                   $_SESSION['level'] = 0;
                   $_SESSION['seconds'] = 0; 
                   echo "form_register";
        }
        else 
        {
            $linha = mysqli_fetch_array($resultado);
            if ($linha['password']==stripslashes($_POST['kbfpassword']))
            {
                $file = glob("users/".$_POST['kbfnickname']."*");
                $_SESSION['nickname'] = $_POST['kbfnickname'];
                $_SESSION['level'] = $linha['level'];
                $_SESSION['seconds'] = $linha['seconds'];
                if (sizeof($file)!=0 and $linha['email']!="")  
                {
                    echo "form_game";
                }
                else  
                {
                    echo "form_register";
                }                     
            }
            else
            {
                echo "The combination nickname/password doesn't exist in our database.";               
            }
        }
    }    
    else 
    {
        echo "Unable to verify nickname. Please, try again later!";

    }
    if ($conecta) mysqli_close($conecta);
}?>

ANDROID JAVA

@Override
protected String doInBackground(String... arg0) {
        try{
            String nickname = arg0[0];
            String password = arg0[1];
            String link="https://savvyartstudio.com/killerbees/signin.php";
            String urlParameters  = URLEncoder.encode("kbfnickname", "UTF-8") + "=" + URLEncoder.encode(nickname, "UTF-8");
            urlParameters += "&" + URLEncoder.encode("kbfpassword", "UTF-8") + "=" +  URLEncoder.encode(password, "UTF-8");
            URL url = new URL(link);
            URLConnection conn = url.openConnection();

            conn.setDoOutput(true);
            OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
            wr.write(urlParameters);
            wr.flush();
            wr.close();

            BufferedReader reader = new BufferedReader(new  InputStreamReader(conn.getInputStream()));
            StringBuilder sb = new StringBuilder();
            String line;
            line = reader.readLine();
            sb.append(line);
            reader.close();

            return sb.toString();
        } catch(Exception e){
            return "Unable to verify nickname. Please, try again later!";
        }

}

Any help would be appreciated!

Tags: android, exception, file, javajava, php