Name Active Layer in expression

Question

I would like to produce an atlas of 5 blocks for 16 variables. So for each atlas I display a layer who represent a variable. For each map in atlas I'm able de set a title with display block name with something like that :

'NDVI ' + "block_name_field"

But I have 16 variables and I don't want to handwrite it. Is code like that possible ?

Active_layer_name + "block_name_field"

Answer 1

In the plug-in Expressions Plus FR (derived from the original from N. Woodrow) you have a function called NamePathActiveLayer that almost does the job (you have at least file name of active layer ...)

or (better, i suppose) :

write your own expression, go in the expression dialog box, activate the function editor tab and try the following code :

    from qgis.core import *
    from qgis.gui import *
    from qgis.utils import iface

    @qgsfunction(args='auto', group='create_your_own_group')
    def ActiveLayerName(feature, parent):
      layer = iface.activeLayer()
      if layer != None :
      return layer.name()

You will have to save the code and the new function should be available (at qgis restart i think ...)