The Google OpenSocial specifications describe different features that can be used, but eXo Platform implements only some of them. See the code of the following files:

The following is a simple procedure to set preferences for Hello World gadget. You can get the source here.

In HelloGadget.xml file:

In summary, the complete content of the HelloGadget.xml file will be:

<?xml version="1.0" encoding="UTF-8" ?>

<Module>

    <ModulePrefs author="eXoPlatform"

    title="Hello World"

    directory_title="Hello World"

    description="The simplest gadget"

    height="300">

        <Require feature="setprefs"/>

    </ModulePrefs>

    <UserPref 

        name="welcome" display_name="Welcome message" 

        default_value="Welcome to Hello World gadget!" required="true"/>

    <Content type="html">

        <![CDATA[

            <link rel="stylesheet" type="text/css" href="/eXoResources/skin/bootstrap/css/bootstrap.css" />

            <script src="/exo-gadget-resources/script/jquery/1.6.2/jquery.min.js"></script>

            <script type="text/javascript">

            $("body").live("click", ".hello .btn", function() {

            $(".hello h6").css("color", "green");

            });

            var getUserPrefs = function() {

            var prefs = new _IG_Prefs(__MODULE_ID__);

            var welcome_message = prefs.getString("welcome");

            $(".hello .alert-info h6").text(welcome_message);

            };

            gadgets.util.registerOnLoadHandler(getUserPrefs);

            </script>

            <div class='hello well'>

            <h2>Hello</h2>

            <div class='alert alert-info'>

            <h6></h6>

            </div>

            <p>Click <a class='btn btn-primary'>here</a> to change the default color of the welcome message.

            <p><i>Powered by eXo Platform.</i></p>

            </div>

            ]]>

    </Content>

</Module>

The Hello World gadget now appears with a pencil icon that allows changing gadget preferences.