Showing the number of currently selected layers in QGIS

Question

Although this should seem to be very straightforward, I cannot find out how to see the number of layers I have currently selected in QGIS. For example, in the example below I want to see somewhere in the GUI the number 5, or be able to somehow retrieve this number:

Obviously, with only five layers selected, I can directly see how many layers I have selected. However, with a lot of layers, it can become an arduous task if I have to count each layer myself. I want to quickly compare the number of layers I have in two different sets of layers. Ideally, I would also be able to see the number of layers within a layer (sub)group (e.g. "Input [X]", where 'X' is the number of layers in the group).

Is there something I should change in the QGIS View settings? Or is there any other method to quickly retrieve this number?

Answer 1

You can use this script. It adds a toolbar as seen in the image and shows how many layers are selected.

label = QLabel("Selected Layers Count:")
count = QLabel()

tree_view = iface.layerTreeView()
c = len(tree_view.selectedLayers())
count.setText(str(c))

tb = iface.addToolBar("Selected layers")
tb.addWidget(label)
tb.addWidget(count)

def show_selected_layers_count():
    c = len(tree_view.selectedLayers())
    count.setText(str(c))

tree_view.selectionModel().selectionChanged.connect(show_selected_layers_count)

Answer 2

To extend the great solution by @Kadir Şahbaz, you could do something like this to get a count per group:

p = QgsProject.instance()
root = p.layerTreeRoot()
view = iface.layerTreeView()

## TOOLBAR
tb = iface.addToolBar("Selected layers")

def show_selected_layers_count():
    tb.clear()
    tb.addWidget(QLabel('Selected layers per group:      '))
    for child in root.children():
        if root.isGroup(child):
            label = QLabel(f'{child.name()}: ')
            selected_layers = []
            for selectedLayer in view.selectedNodes():
                if selectedLayer.parent() == child:
                    selected_layers.append(selectedLayer)
            
            count = len(selected_layers)
                        
            count_label = QLabel(str(count) + '    ')
            tb.addWidget(label)
            tb.addWidget(count_label)
  
con = view.selectionModel().selectionChanged.connect(show_selected_layers_count)

# to disconnect the function from the signal
#view.selectionModel().selectionChanged.disconnect(con)