[OpenLayers-Users] Overriding overlay select to force a reload of the toggled layer

[Jay Douillard]

Adrian,

You need to register events to fire when want refreshing to occur.
You can use the visibility property of a layer to test if it is visible and only refresh those layers that are.
http://dev.openlayers.org/releases/OpenLayers-2.8/doc/apidocs/files/OpenLayers/Layer-js.html#OpenLayers.Layer.visibility

http://dev.openlayers.org/apidocs/files/OpenLayers/Events-js.html
----
Jay 


----- Original Message -----
From: "Adrian Popa" <adrian_gh.popa at romtelecom.ro>
To: users at openlayers.org
Sent: Tuesday, July 14, 2009 11:27:17 PM GMT -08:00 US/Canada Pacific
Subject: [OpenLayers-Users] Overriding overlay select to force a reload of the toggled layer

Hi everybody,

I have several overlay vector layers that get their data in KML format 
from some server-side scripts. The data is highly dynamic, so it needs 
to be refreshed constantly (this is solved). The problem appears if only 
one overlay layer is selected (visible), I need to refresh all overlay 
layers so that if the user toggles another overlay, he will have the 
most recent data. I would like to reduce the overhead on the server and 
client side and only refresh the visible overlay layers, and to force a 
refresh of a layer whenever the user makes it visible. For this I would 
have to override the function that runs when a layer is selected in the 
layer switcher and call another refresh function before the layer is 
made visible. Can anyone point me in the right direction?

P.S. I would like to do this without editing the openlayers code; 
instead I would like to override/overload the function for my objects only.

Thanks,
Adrian

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