Question

I’m currently developing and I came up to the following question:
How can/should I store basic information, such as unlocked items and levels between devices.
Of course, I store them within preference files.

But what if the user buys a new phone and wants to continue playing on there?
(Shared-)Preferences won’t be duplicated.

Thus, is there any (from google) recommended way (cloud?) to solve this issue?

Answer 1

I’m no expert, but the way I do this is with an online SQL database. Have the device connect to it, and save/load any data you need. I know this will not work with files, only text-based information. I also do this using Flash. If this is your route I can share some code.

Ok, so you need 3 things if you are doing this in flash: Flash (duh), PHP files, and a SQL server (I have a MYSQL server).

How it will work is flash will load php, php will do it’s thing (like making changes to the database) and spit back it’s results to flash.

Let’s say we want to get all usernames from the database.

Database

The table name is called “Players” with a single column called “u_id”

Flash

var loader:URLLoader; //makes a loader that will "load" the php page

public function DoIt()
{
    loader = new URLLoader();
    loader.addEventListener(Event.COMPLETE, loaderComplete);
    loader.load(new URLRequest("http://yourDomain.com/thePHPFile.php?arg=42"));
}

public function loaderComplete(e:Event):void
{
    var returnXML:XML; //we are assuming the return values are in xml format, trust me, this might be easier

    for each (var ListItem:XML in returnXML..Users) //you might need to change this "users" to be the root of the xml file
    {
        var userName:String = ListItem.u_id.toString();
        //you can do what you want with the data here
    }
}

PHP

Now it might not be required, but I try to make sure the PHP files and the DB is on the same host, so that I can do “localhost” as the host name

<?php

    $argumentVar = $_GET["arg"]; //not using this, just showing it's possible
    $connect = mysql_connect("localhost", "db_username", "db_password");

    if(!$connect)
    {
        die("error connecting to DB" . mysql_error());
    }

    $db_selected = mysql_select_db("the_name_of_the_db", $connect);

    if(!$db_selected)
    {
        die("error selecting db" . mysql_error());
    }

    $table_name = "Players" //this is the name of your database
    $sql = "SELECT * FROM $table_name;"; //not sure if you need ending ';'

    $dbresult = mysql_query($sql, $connect); //this is where all your data comes into

    //and now to save all the information to a xml file
    $doc = new DOMDocument('1.0');
$root = $doc->createElement('root');
$root = $doc->appendChild($root);

    while($row = mysql_fetch_assoc($dbresult)) 
{
    $occ = $doc->createElement($table_name);
    $occ = $root->appendChild($occ);

    foreach ($row as $fieldname => $fieldvalue)
    {
        $child = $doc->createElement($fieldname);
        $child = $occ->appendChild($child);

        $value = $doc->createTextNode($fieldvalue);
        $value = $child->appendChild($value);
    }
}

$xml_string = $doc->saveXML();
echo $xml_string;
?>

Ok, go play with that, it should start you on the right path.