Apply transparency on a WFS layer (PyQGIS)

Question

I'm trying to make a wfs layer transparent, but it gives me a mistake, but I can't solve it until now.

This is my code:

uri ='http://gstore.unm.edu/apps/rgis/datasets/6ca5428a-a78c-4c82-8120-da70dc92f2cc/services/ogc/wfs?SERVICE=wfs&VERSION=1.0.0&REQUEST=GetFeature&TYPENAME=tl_2010_35_state10'

wfslayer = QgsVectorLayer(uri, "MEXICO", "WFS")

QgsProject.instance().addMapLayer(wfslayer)

So far everything is correct

 renderer = wfslayer.rendererV2()

In this function it gives me the mistake

I don't know if it's a problem with the version (QGIS 3.16.2) of the program or with the code.

It no longer lets me put the rest of the code.

symbol = renderer.symbol()
symbol.setAlpha(0.5)

Answer 1

You actually only need to add this line to your code after loading the WFS layer:

wfslayer.setOpacity(0.5) # enter opacity (transparency) value from 0-1

So overall, your code should be:

uri ='http://gstore.unm.edu/apps/rgis/datasets/6ca5428a-a78c-4c82-8120-da70dc92f2cc/services/ogc/wfs?SERVICE=wfs&VERSION=1.0.0&REQUEST=GetFeature&TYPENAME=tl_2010_35_state10'
wfslayer = QgsVectorLayer(uri, "MEXICO", "WFS")
wfslayer.setOpacity(0.5)
QgsProject.instance().addMapLayer(wfslayer)

From the documentation: https://qgis.org/pyqgis/3.0/core/Vector/QgsVectorLayer.html#qgis.core.QgsVectorLayer.setOpacity

I suspect you were trying to implement an approach for the previous version of QGIS (2.X), but with QGIS 3.X onwards there are changes to the API for applying layer symbology.