[Qgis-user] Custom form init function changes - Kind of API break

[Nathan Woodrow]

Hey All,

This is a just a quick email to let everyone know that I have changed
the way that arguments are passed to a layers Init Python function.
That is the option that you find in the Layer Properties dialog on the
General tab. If you are using this then this will affect you and you
will know what I'm talking about.

I have changed it so that the reference to the layer and feature are
now passed into the function rather then just ids.  The issue with
just passing the feature id was that you couldn't get access to the
new feature and geometry because you were given a 0 as the id and 0 is
a valid id for already existing feature.

So now instead of this:

def myFunction(dialog, layer_id, feature_id)

where layer_id and feature_id are integers.  You now do this:

def myFunction(dialog, layer, feature)

layer is a instance of QgsVectorLayer
feature is a instance of QgsFeature

You can now do things like:

def myFunction(dialog, layer, feature):
      id = layer.id()
      name = layer.name()
      geom = feature.geometry()
      geom.length()
      # etc

This change will break your custom form logic if your code is
expecting a interger for the feature argument but you get a QgsFeature

Just a FYI so you don't freak out when you form logic doesn't work anymore.

- Nathan