How to filter out layers with QgsMapLayerComboBox?

Question

I am using Qt Designer 4.8.5 to develop a plugin (with QGIS 2.14.3-Essen).

I recently started to use QgsMapLayerComboBox widgets instead of the conventional Combo Box widget. However, I want to filter out a number of layers so that only a few are shown.

When I used the Combo box widget, here is the code:

root = QgsProject.instance().layerTreeRoot()
main_group = root.findGroup('Main group')
layers = []
for group in main_group.children():
    for layer in group.children():                
        layers.append(layer.layerName())
self.dockwidget.combo_box.clear()
self.dockwidget.combo_box.addItems(sorted(layers))

---

How can I translate the above code to work with QgsMapLayerComboBox? I have seen the QgsMapLayerComboBox.setExceptedLayerList() but not exactly sure how to create such a list.

Answer 1

Guess it was easier than I thought, I just had to create a list of QgsMapLayers from a group I want excluded in the QgsMapLayerComboBox:

root = QgsProject.instance().layerTreeRoot()
other_group = root.findGroup('Other group')
layers = []
for group in other_group.children():
    for layer in group.children():
        layerList = QgsMapLayerRegistry.instance().mapLayersByName(layer.layerName())[0]
        layers.append(layerList)
self.dockwidget.combo_box.setExceptedLayerList(layers)