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NiceGUI: Show a confirmation popup

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The NiceGUI dialog element can be used to create a confirmation popup or modal. With an awaitable dialog, it is easy to create an “Are you sure?” popup, to let a user confirm before doing an action. The official documentation provides a good example of a single dialog, but if you were to follow the same approach for multiple dialogs then the boilerplate code quickly multiplies.

To minimise the boilerplate code, you can re-use the same popup in multiple places.

Following is a simple example of one popup being used by two menus items:

class MyGUI:
    def __init__(self, *args, **kwargs):
        # Default text to display in the popup.
        self.popup_text = "Are you sure?"

        async def show_popup(_popup_text: str, func):
            """Call this function to trigger the popup.

            The functon `func` is only called if "Yes" is clicked in the dialog.
            """
            self.popup_text = _popup_text
            result = await popup_dialog
            if result == "Yes":
                func()

        # Define a single yes/no dialog that gets re-used for all the popups.
        with ui.dialog() as popup_dialog, ui.card():
            # Bind the text for the question, so that when `self.popup_text`
            # gets updated by `show_popup`, the text in the dialog also gets
            # updated.
            ui.label().bind_text_from(self, "popup_text")
            with ui.row():
                ui.button("Yes", on_click=lambda: popup_dialog.submit("Yes"))
                ui.button("No", on_click=lambda: popup_dialog.submit("No"))

        # Create a simple menu with some buttons, which call `show_popup` when
        # clicked and change the text for the question. The passed in `func`
        # is only executed by `show_popup` if the "Yes" button is pressed.
        with ui.button(icon="menu"):
            with ui.menu() as menu:
                ui.menu_item(
                    "Destroy widget",
                    lambda: show_popup(
                        "Do you really want to destroy the widget?",
                        self._action_widget_destroy
                    ),
                )
                ui.menu_item(
                    "Reset to defaults",
                    lambda: show_popup(
                        "Are you sure you want to reset to defaults?",
                        self._action_config_reset,
                    ),
                )

    def _action_widget_destroy(self):
        """Action: destroy the widget."""

    def _action_config_reset(self):
        """Action: reset to defaults."""

This code works by defining a single dialog, binding to the text that is shown in the dialog, and updating the bound text each time the dialog is used. The action functions are only called if “Yes” is chosen on the popup.