Ability to turn off all base mapping in flex viewer 2.5

[HarrietMcQuade]

Hello.

I have a request from a user that would like to be able to switch all base mapping off completely. In order to view one of the dynamic layers on its own.
Is there a button or widget I can add to the viewer to turn all layers shown in my map switcher off completely so that I just get white space?
I am using version 2.5 of the viewer, ArcGIS Server 10 and compiled code.

I know it is a bit of a strange request but if anyone can help me I would appreciate it.

Harriet

[MayJeff]

I am using flexviewer 3.2.  I set addarcgisbasemaps to false and also comment out basemap on config.xml.  see below:
<map wraparound180="true" initialextent="-14083000 3139000 -10879000 5458000" fullextent="-20000000 -20000000 20000000 20000000" top="40" addarcgisbasemaps="false" esrilogovisible="false">

        <!--basemaps>
            ...
        </basemaps-->
        <operationallayers>
            ...
        </operationallayers>
</map>

Thanks.

[RobertScheitlin__GISP]

Harriet,

  This question has been answered a few times in the forums.

All you need to do is add a basemap with a blank url.

<basemaps>
        <layer label="Aerial" type="tiled" visible="true" alpha="1" url="http://server.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer" icon="assets/images/basemap_imagery.jpg" />
        <layer label="Blank" type="dynamic" visible="false" url="" />    
</basemaps>

Assuming you are using the maps addarcgisbasemaps="true" then you need to specify your default basemap you want selected as I have above by putting the Aerial basemap.

[AnthonyGiles]

Harriet,

If you want to give the user the ability to tone down the base map to Gray scale or desaturated, or turn off the base map completely then I have published a widget here:

http://www.arcgis.com/home/item.html?id=3d1ea673ad15413db81262a4e73184ac

Regards

Anthony

[RhettZufelt]

The method Robert mentioned doesn't work for me as I want my blank one listed first in the list.  If done with a blank URL, I don't get the tile info, and the other tiled layers error out.

What I have done is create an empty ArcMap (actually, one layer with color = null) document in my wkid, then published to a service, and created the same cache tiles as the rest of my map.  Works like a charm.

R_