cartogram plugin doesn't see join fields

[bjquinn]

I have joined a .csv file to the data in my .shp file (well, the .dbf, obviously), and I can see the data in the attribute table, but the field doesn't show up on the list of available fields in the drop down to choose a data field in the cartogram creator plugin.

[bjquinn]

There are hints here -- http://lists.osgeo.org/pipermail//qgis-developer/2013-January/023868.html.

I tried modifying references to the provider with references to the layer, and I've gotten close. I can get the join field to show up on the drop down list (also requires removing if statement filtering out string fields), and I can get the 1st iteration to run, but it bombs on the 2nd iteration. Probably has to do with the fact that I don't know a lot about the QGIS plugin API.