Geolocation using Gears and Geode

Location based Services applications are requiring more and more that the geographical coordinates (or at least the neighborhood) of the user be automatically detected to create a more seamless and streamlined experience. Google Gears with its geolocation API and Mozilla Labs with its Geode project are making the W3C geolocation specification a reality. With such democratization of services, it would be nice to have geolocation as a native function in the flash player, so would be a JSON parser (but that is a topic of conversation for another day). Until then, we have to rely on the browser's capabilities to feed that information into the player. This can easily achieved using the ExternalInterface class. In this post, I adopted the geolocation W3C specification and implemented an ActionScript class to wrap the Gears and Geode javascript functions so they can be invoked from a Flex application. Make sure to install Gears and/or Geode to test this application. Using FlexBuilder, the index.template.html has to be adjusted to include the gears_init.js file and the geolocation.js wrapper file as follows:

...
<script type="text/javascript" src="AC_OETags.js"></script>
<script type="text/javascript" src="gears_init.js"></script>  
<script type="text/javascript" src="geolocation.js"></script>
<style>
...

The registration of the callback functions is done by creating an instance of the GeoLocation class:

...
<geolocation:GeoLocation id="geolocation"/>
...

The position of the web application can be determined using something of the form:

...
geolocation.getCurrentPosition( currentPositionSuccessHandler, currentPositionFaultHandler );
...

Check out the application here. And like usual, you can download the source from here.