Re: [udig-devel] Re: FW: Add layer programmatically/1.1 question

[Jesse Eichar <jesse.eichar@xxxxxxxxxxxxxx>]

Hi Stephan,

In order to have a functioning layer you need to do:

1.  Create a layer
2.  Set the ID of the layer to be equal to the ID of the IGeoResource  
that it represents.

You can think of a layer as an IGeoResource with a style.  That is  
simplistic but it is more or less the idea.  So when you use  
ApplicationGIS.addLayersToMap you only need the IGeoResource.

So if you are satisfied with the default style then you can simply use  
ApplicationGIS.addLayersToMap to add layer to a map.  However if you  
have a specific style or some other configuration that is done to the  
layer then you want to use the AddLayerCommand or the AddLayersCommand.

Jesse

On 17-Oct-08, at 3:31 AM, Jody Garnett wrote:

> My understanding the two are very similar;
> - option one sends the AddLayerCommand to the map
> - option 2 creates a bunch of layers from the provided list of  
> GeoResources and inserts these new layers at the indicated position.
>
> There have been a number of off lists questions about creating and  
> managing maps "by hand"; in general you can ignore all the udig  
> stuff and create your own MapCommand; in the body of the command you  
> can do anything you want...
>
> Jody
>
> Stephen Kilburn wrote:
> > To add a layer programmatically,
> > http://udig.refractions.net/confluence/display/DEV/How+do+I+add+a+layer+prog
> > rammatically says:
> >
> > -for uDig 1.0:
> >  IMap map;
> >  map.sendCommandASync(new AddLayerCommand(layer) );
> >
> > -for uDig 1.1:
> >  ApplicationGIS.addLayersToMap(map, layers, startposition, project);
> >
> > But addLayersToMap takes a List<IGeoResource>, not a List<ILayer>,  
> > and when
> > I try:
> >
> >  Layer layer = ProjectFactory.eINSTANCE.createLayer();
> >  // ... populate the new layer with geo and styling ...
> >  IGeoResource igr = (IGeoResource) layer;
> >
> > I get a ClassCastException.
> >
> > Do I need to use the 1.0 syntax to add *layers* or am I missing  
> > something?
> > (Latter exceedingly likely!)
> > _____________________________________________________________
> > Stephen Kilburn, GeoPraxis Inc.
>
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