Update _favorite_ids in BaseMaterialsModel._update

And make all subclasses run its super _update as well to make sure that this gets updated for them. It's necessary for the _createMaterialItem functionality because it needs to add an is_favorite role.

Contributes to issue CURA-6600.

cura/Machines/Models/BaseMaterialsModel.py

@@ -4,6 +4,8 @@
 from typing import Optional, Dict, Set
 
 from PyQt5.QtCore import Qt, pyqtSignal, pyqtProperty
+
+from UM.Preferences import Preferences
 from UM.Qt.ListModel import ListModel
 
 import cura.CuraApplication  # Imported like this to prevent a circular reference.
@@ -111,7 +113,7 @@ class BaseMaterialsModel(ListModel):
     ## This is an abstract method that needs to be implemented by the specific
     #  models themselves.
     def _update(self):
-        pass
+        self._favorite_ids = set(Preferences.getInstance().getValue("cura/favorite_materials").split(";"))
 
     ## This method is used by all material models in the beginning of the
     #  _update() method in order to prevent errors. It's the same in all models

cura/Machines/Models/FavoriteMaterialsModel.py

@@ -19,12 +19,10 @@ class FavoriteMaterialsModel(BaseMaterialsModel):
         self._update()
 
     def _update(self):
+        super()._update()
         if not self._canUpdate():
             return
 
-        # Get updated list of favorites
-        self._favorite_ids = self._material_manager.getFavorites()
-
         item_list = []
 
         for root_material_id, container_node in self._available_materials.items():

cura/Machines/Models/GenericMaterialsModel.py

@@ -10,12 +10,10 @@ class GenericMaterialsModel(BaseMaterialsModel):
         self._update()
 
     def _update(self):
+        super()._update()
         if not self._canUpdate():
             return
 
-        # Get updated list of favorites
-        self._favorite_ids = self._material_manager.getFavorites()
-
         item_list = []
 
         for root_material_id, container_node in self._available_materials.items():

cura/Machines/Models/MaterialBrandsModel.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2018 Ultimaker B.V.
+# Copyright (c) 2019 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
 from PyQt5.QtCore import Qt, pyqtSignal
@@ -27,10 +27,9 @@ class MaterialBrandsModel(BaseMaterialsModel):
         self._update()
 
     def _update(self):
+        super()._update()
         if not self._canUpdate():
             return
-        # Get updated list of favorites
-        self._favorite_ids = self._material_manager.getFavorites()
 
         brand_item_list = []
         brand_group_dict = {}