QGIS 3 : Qt Signal emmitted when selecting a layer?

Question

I am currently writing a QGIS 3 plugin. I would like to catch the signal emmited each time the user selects a new layer in the layer panel.

I have already searched in the QGIS API (QgsProject, QgsLayerTree, QgsLayerTreeView, ...)

QgsLayerTreeView has a signal currentLayerChanged but I cannot find how to connect QgsLayerTreeView to QgsProject.instance().

Does anyone has an idea on what is the solution or at least where I can find some information?

Answer 1

You can connect this signal to iface for example.

def currentLayerChanged(layer):
    print(layer.name())

iface.currentLayerChanged.connect(currentLayerChanged)

Or if you want make connection using QgsLayerTreeView

def onChange(layer):
  print("Current Layer: " + str(layer.name()))

# connect to the signal
view = iface.layerTreeView()
view.currentLayerChanged.connect(onChange)

Check the lutraconsulting blog for more information. Note that this site use QGIS 2.4