Function set_combo_items

deeplabcut/gui/components.py:73–114

Safely replaces all items in a QComboBox and sets the current index, ensuring that the `currentTextChanged` signal is emitted exactly once (and only if items are present). This method suppresses intermediate signal emissions that can be triggered by `clear()` and `addItems()` — both

(combo_box: QtWidgets.QComboBox, items: list[str], index: int = 0)

def set_combo_items(combo_box: QtWidgets.QComboBox, items: list[str], index: int = 0):
    """Safely replaces all items in a QComboBox and sets the current index, ensuring
    that the `currentTextChanged` signal is emitted exactly once (and only if items are
    present).

    This method suppresses intermediate signal emissions that can be triggered
    by `clear()` and `addItems()` — both of which may emit multiple signals
    depending on the underlying Qt model and signal connections.

    It also handles the edge case where the item at the target index is already
    selected: by default, Qt will not emit a signal if the index doesn't change.
    To ensure consistent behavior, this method temporarily sets the index to -1
    (i.e., no selection), which is done with signals blocked, then restores the
    intended index — causing the signal to emit once and only once.

    Parameters:
        combo_box (QComboBox): The combo box to update.
        items (list of str): New items to populate the combo box.
        index (int): The index to select after updating items. Defaults to 0.

    Note:
        - If the items list is empty, no item will be selected and no signal will be emitted.
        - This method is designed to be safe for use with PySide, where signals
          cannot be manually emitted, and future-proof if multiple slots are connected.
    """
    combo_box.blockSignals(True)
    combo_box.clear()
    combo_box.addItems(items)
    combo_box.blockSignals(False)

    if not items:
        combo_box.setCurrentIndex(-1)
        return

    current = combo_box.currentIndex()
    if current == index:
        # Temporarily change index to suppress duplicate signal
        combo_box.blockSignals(True)
        combo_box.setCurrentIndex(-1)
        combo_box.blockSignals(False)

    combo_box.setCurrentIndex(index)


class BodypartListWidget(QtWidgets.QListWidget):