2.4/samples/mobilewebapp/src/main/java/com/google/gwt/sample/mobilewebapp/FormFactor.gwt.xml

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

<!-- Defines the formfactor property and its provider function. -->
<module>

  <!-- Determine if we are in a mobile browser. -->
  <define-property name="formfactor" values="desktop,tablet,mobile"/>
  <collapse-property name="formfactor" values="*"/>

  <property-provider name="formfactor">
  <![CDATA[
      // Look for the formfactor as a url argument.
      var args = location.search;
      var start = args.indexOf("formfactor");
      if (start >= 0) {
        var value = args.substring(start);
        var begin = value.indexOf("=") + 1;
        var end = value.indexOf("&");
        if (end == -1) {
          end = value.length;
        }
        return value.substring(begin, end);
      }

      // Detect form factor from user agent.
      var ua = navigator.userAgent.toLowerCase();
      if (ua.indexOf("iphone") != -1 || ua.indexOf("ipod") != -1) {
        // iphone and ipod.
        return "mobile";
      } else if (ua.indexOf("ipad") != -1) {
        // ipad.
        return "tablet";
      } else if (ua.indexOf("android") != -1 || ua.indexOf("mobile") != -1) {
        /*
         * Android - determine the form factor of android devices based on the diagonal screen
         * size. Anything under six inches is a phone, anything over six inches is a tablet.
         */
        var dpi = 160;
        var width = $wnd.screen.width / dpi;
        var height = $wnd.screen.height / dpi;
        var size = Math.sqrt(width*width + height*height);
        return (size < 6) ? "mobile" : "tablet";
      }
      
      // Everything else is a desktop.
      return "desktop";
  ]]>
  </property-provider>

</module>