[OpenLayers-Users] Permalink doesn't update on addlayer/removelayer

[Andreas Hocevar]

Ok, I do see yours and Marc's point now. You are not talking about using the Permalink control as-is, but with a custom createParams method and a custom ArgParser. In this case it can indeed be useful to listen to addlayer/removelayer.

So yes, the Peramlink control could be improved with a patch containing the snipped posted by Marc.

Regards,
Andreas.
 
On Aug 24, 2010, at 15:30 , Slawomir Messner wrote:

>  Hi all,
> I thought permalink should have the information about visibility(and 
> other stuff) and should refresh when this values change, then for me 
> it's a bug when the initial values are not stored in the link (it's like 
> the first change).
> The other thing is the need for extra information about layers to load 
> them at the beginning. Thanks for the link Andreas, I will visit it 
> tomorrow. I didn't look for an external solution because Permalink and 
> ArgParams are easy to extend and the informations are not complex. But 
> who knows, maybe there will be more data to store, so I will visit your 
> link, thx.
> Regards,
> Slawomir
> 
> Am 24.08.2010 15:15, schrieb Marc Jansen:
>> Hi Andreas,
>> 
>> first of all, sorry for cross-posting in the past. I thought it was
>> useful in this case.
>> 
>> I'd disagree about the not handling of the layeradd/layerremove event
>> for the Permalink-control -- but can easily live without this addition
>> to OpenLayers :-)
>> 
>> Your suggestions of alternative ways of handling application "state" are
>> valid and often better suited, yet I think the addition of two
>> additional listeners to the control would be very intuitive.
>> 
>> Best regards,
>> 
>> Marc
>> 
>> 
>> 
>> On 24.08.2010 14:49, Andreas Hocevar wrote:
>>> Hi,
>>> 
>>> first of all, please don't cross-post dev and users.
>>> 
>>> I am not sure if a permalink as provided by OpenLayers is what you really want for applications where the user can add or remove layers. The permalink only stores the visible/invisible state of the available layers in their order. It does not know anything about what these layers are. So a permalink will look exactly the same for any map with the same extent with let's say 3 layers that are all visible.
>>> 
>>> If you want to store information on what layers are actually configured, you should look into Format.WMC, Format.OWS or solutions like the OpenGeo Suite's GeoExplorer (http://suite.opengeo.org/geoexplorer), which stores layer configurations in a database and provides a permalink with a map id.
>>> 
>>> Regards,
>>> Andreas.
>>> 
>>> On Aug 24, 2010, at 14:31 , Marc Jansen wrote:
>>> 
>>> 
>>>> Hi Slawomir,
>>>> 
>>>> I'd consider this a bug with a (on first sight) reasonable easy fix:
>>>> 
>>>> In the Permalinks draw-method:
>>>> 
>>>>          this.map.events.on({
>>>>              'moveend': this.updateLink,
>>>>              'changelayer': this.updateLink,
>>>>              'changebaselayer': this.updateLink,
>>>>              'addlayer': this.updateLink,
>>>>              'removelayer': this.updateLink,
>>>>              scope: this
>>>>          });
>>>> 
>>>> Or one could think of triggering a changelayer event when a layer has
>>>> been added/removed in Map.js.
>>>> 
>>>> I am unsure which design is better, so I'd suggest opening up a ticket
>>>> (I cc'ed the developer list so the core developers notice this discussion).
>>>> 
>>>> Regards,
>>>> Marc
>>>> 
>>>> 
>>>> 
>>>> 
>>>> On 24.08.2010 13:53, Slawomir Messner wrote:
>>>> 
>>>>>    Hello,
>>>>> Does anyone know why Permalink doesn't listen to addlayer/removelayer?
>>>>> Every time I add a new layer I have to change a property(i.e.
>>>>> visibility) to refresh the link. It's a bug or a feature?
>>>>> Regards,
>>>>> Slawomir
>>>>> 
>>>>> 
>>>> _______________________________________________
>>>> Dev mailing list
>>>> Dev at openlayers.org
>>>> http://openlayers.org/mailman/listinfo/dev
>>>> 
>>> 
>> 
> 
> 
> -- 
> -----------------------------------------------
> Slawomir Messner
> Forschungszentrum "Deutscher Sprachatlas"
> 06421-28-24981
> 
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-- 
Andreas Hocevar
OpenGeo - http://opengeo.org/
Expert service straight from the developers.