Move some convoluted logic from QML into Python

plugins/MachineSettingsAction/MachineSettingsAction.py

@@ -122,6 +122,40 @@ class MachineSettingsAction(MachineAction):
 
         return len(self._global_container_stack.getMetaDataEntry("machine_extruder_trains"))
 
+    @pyqtSlot(int)
+    def setMachineExtruderCount(self, extruder_count):
+        machine_manager = Application.getInstance().getMachineManager()
+        extruder_manager = ExtruderManager.getInstance()
+
+        definition_changes_container = self._global_container_stack.findContainer({"type": "definition_changes"})
+        if not self._global_container_stack or not definition_changes_container:
+            return
+
+        if extruder_count == self._global_container_stack.getProperty("machine_extruder_count", "value"):
+            return
+
+        extruder_material = None
+        if extruder_count == 1 and machine_manager.hasMaterials:
+            extruder_material = machine_manager.allActiveMaterialIds[machine_manager.activeStackId]
+
+        definition_changes_container.setProperty("machine_extruder_count", "value", extruder_count)
+        self.forceUpdate()
+
+        if extruder_count > 1:
+            # multiextrusion; make sure one of these extruder stacks is active
+            if extruder_manager.activeExtruderIndex == -1:
+                extruder_manager.setActiveExtruderIndex(0)
+        else:
+            # single extrusion; make sure the machine stack is active
+            if extruder_manager.activeExtruderIndex > -1:
+                extruder_manager.setActiveExtruderIndex(-1);
+
+            if extruder_material:
+                # restore material on global stack
+                # MachineManager._onGlobalContainerChanged removes the global material of multiextruder machines
+                machine_manager.setActiveMaterial(extruder_material);
+
+
     @pyqtSlot()
     def forceUpdate(self):
         # Force rebuilding the build volume by reloading the global container stack.

plugins/MachineSettingsAction/MachineSettingsAction.qml

@@ -377,48 +377,11 @@ Cura.MachineAction
                                     currentIndex: machineExtruderCountProvider.properties.value - 1
                                     onActivated:
                                     {
-                                        if(machineExtruderCountProvider.properties.value == index + 1)
-                                        {
-                                            return;
-                                        }
-
-                                        var extruder_material;
-                                        if(index == 0 && Cura.MachineManager.hasMaterials)
-                                        {
-                                            // setting back to single extrusion
-                                            extruder_material = Cura.MachineManager.allActiveMaterialIds[Cura.MachineManager.activeStackId];
-                                        }
-
-                                        machineExtruderCountProvider.setPropertyValue("value", index + 1);
-                                        manager.forceUpdate();
+                                        manager.setMachineExtruderCount(index + 1);
                                         base.extruderTabsCount = (index > 0) ? index + 1 : 0;
-
-                                        if(index > 0)
-                                        {
-                                            // multiextrusion; make sure one of these extruder stacks is active
-                                            if(ExtruderManager.activeExtruderIndex == -1)
-                                            {
-                                                ExtruderManager.setActiveExtruderIndex(0);
-                                            }
-                                        }
-                                        else
-                                        {
-                                            // single extrusion; make sure the machine stack is active
-                                            if(ExtruderManager.activeExtruderIndex != -1)
-                                            {
-                                                ExtruderManager.setActiveExtruderIndex(-1);
-                                            }
-                                            if(extruder_material)
-                                            {
-                                                // restore material on global stack
-                                                // MachineManager._onGlobalContainerChanged removes the global material of multiextruder machines
-                                                Cura.MachineManager.setActiveMaterial(extruder_material);
-                                            }
-                                        }
                                     }
                                 }
 
-
                                 Label
                                 {
                                     text: catalog.i18nc("@label", "Nozzle size")