feat(device combobox): add option to insert an empty element

bec_widgets/widgets/control/device_input/device_combobox/device_combobox.py

@@ -5,6 +5,7 @@ from qtpy.QtGui import QPainter, QPaintEvent, QPen
 from qtpy.QtWidgets import QComboBox, QSizePolicy
 
 from bec_widgets.utils.colors import get_accent_colors
+from bec_widgets.utils.error_popups import SafeProperty
 from bec_widgets.widgets.control.device_input.base_classes.device_input_base import (
     BECDeviceFilter,
     DeviceInputBase,
@@ -61,6 +62,7 @@ class DeviceComboBox(DeviceInputBase, QComboBox):
         self._callback_id = None
         self._is_valid_input = False
         self._accent_colors = get_accent_colors()
+        self._set_first_element_as_empty = False
         # We do not consider the config that is passed here, this produced problems
         # with QtDesigner, since config and input arguments may differ and resolve properly
         # Implementing this logic and config recoverage is postponed.
@@ -93,6 +95,31 @@ class DeviceComboBox(DeviceInputBase, QComboBox):
         self.currentTextChanged.connect(self.check_validity)
         self.check_validity(self.currentText())
 
+    @SafeProperty(bool)
+    def set_first_element_as_empty(self) -> bool:
+        """
+        Whether the first element in the combobox should be empty.
+        This is useful to allow the user to select a device from the list.
+        """
+        return self._set_first_element_as_empty
+
+    @set_first_element_as_empty.setter
+    def set_first_element_as_empty(self, value: bool) -> None:
+        """
+        Set whether the first element in the combobox should be empty.
+        This is useful to allow the user to select a device from the list.
+
+        Args:
+            value (bool): True if the first element should be empty, False otherwise.
+        """
+        self._set_first_element_as_empty = value
+        if self._set_first_element_as_empty:
+            self.insertItem(0, "")
+            self.setCurrentIndex(0)
+        else:
+            if self.count() > 0 and self.itemText(0) == "":
+                self.removeItem(0)
+
     def on_device_update(self, action: str, content: dict) -> None:
         """
         Callback for device update events. Triggers the device_update signal.

bec_widgets/widgets/control/device_input/signal_combobox/signal_combobox.py

@@ -1,8 +1,10 @@
+from __future__ import annotations
+
 from bec_lib.device import Positioner
 from qtpy.QtCore import QSize, Signal
 from qtpy.QtWidgets import QComboBox, QSizePolicy
 
-from bec_widgets.utils.error_popups import SafeSlot
+from bec_widgets.utils.error_popups import SafeProperty, SafeSlot
 from bec_widgets.utils.filter_io import ComboBoxFilterHandler, FilterIO
 from bec_widgets.utils.ophyd_kind_util import Kind
 from bec_widgets.widgets.control.device_input.base_classes.device_signal_input_base import (
@@ -54,6 +56,7 @@ class SignalComboBox(DeviceSignalInputBase, QComboBox):
 
         self.setSizePolicy(QSizePolicy.Preferred, QSizePolicy.Fixed)
         self.setMinimumSize(QSize(100, 0))
+        self._set_first_element_as_empty = True
         # We do not consider the config that is passed here, this produced problems
         # with QtDesigner, since config and input arguments may differ and resolve properly
         # Implementing this logic and config recoverage is postponed.
@@ -90,6 +93,31 @@ class SignalComboBox(DeviceSignalInputBase, QComboBox):
                 self.insertItem(0, "Hinted Signals")
                 self.model().item(0).setEnabled(False)
 
+    @SafeProperty(bool)
+    def set_first_element_as_empty(self) -> bool:
+        """
+        Whether the first element in the combobox should be empty.
+        This is useful to allow the user to select a device from the list.
+        """
+        return self._set_first_element_as_empty
+
+    @set_first_element_as_empty.setter
+    def set_first_element_as_empty(self, value: bool) -> None:
+        """
+        Set whether the first element in the combobox should be empty.
+        This is useful to allow the user to select a device from the list.
+
+        Args:
+            value (bool): True if the first element should be empty, False otherwise.
+        """
+        self._set_first_element_as_empty = value
+        if self._set_first_element_as_empty:
+            self.insertItem(0, "")
+            self.setCurrentIndex(0)
+        else:
+            if self.count() > 0 and self.itemText(0) == "":
+                self.removeItem(0)
+
     def set_to_obj_name(self, obj_name: str) -> bool:
         """
         Set the combobox to the object name of the signal.