Source code for arcade.gui.widgets.dropdown

from __future__ import annotations

from copy import deepcopy
from typing import Optional, List, Union

from pyglet.event import EVENT_HANDLED

import arcade
from arcade.gui import UIEvent, UIMousePressEvent
from arcade.gui.events import UIOnChangeEvent, UIOnClickEvent
from arcade.gui.ui_manager import UIManager
from arcade.gui.widgets import UILayout, UIWidget
from arcade.gui.widgets.buttons import UIFlatButton
from arcade.gui.widgets.layout import UIBoxLayout


class _UIDropdownOverlay(UIBoxLayout):
    """
    Represents the dropdown options overlay.

    Currently only handles closing the overlay when clicked outside of the options.
    """

    # TODO move also options logic to this class

    def show(self, manager: UIManager):
        manager.add(self, layer=UIManager.OVERLAY_LAYER)

    def hide(self):
        """Hide the overlay."""
        self.parent.remove(self)

    def on_event(self, event: UIEvent) -> Optional[bool]:
        if isinstance(event, UIMousePressEvent):
            # Click outside of dropdown options
            if not self.rect.collide_with_point(event.x, event.y):
                self.hide()
                return EVENT_HANDLED
        return super().on_event(event)


[docs] class UIDropdown(UILayout): """ A dropdown layout. When clicked displays a list of options provided. Triggers an event when an option is clicked, the event can be read by .. code:: py dropdown = Dropdown() @dropdown.event() def on_change(event: UIOnChangeEvent): print(event.old_value, event.new_value) :param x: x coordinate of bottom left :param y: y coordinate of bottom left :param width: Width of each of the option. :param height: Height of each of the option. :param default: The default value shown. :param options: The options displayed when the layout is clicked. :param style: Used to style the dropdown. """ DIVIDER = None def __init__( self, *, x: float = 0, y: float = 0, width: float = 100, height: float = 20, default: Optional[str] = None, options: Optional[List[Union[str, None]]] = None, style=None, **kwargs, ): if style is None: style = {} # TODO handle if default value not in options or options empty if options is None: options = [] self._options = options self._value = default super().__init__(x=x, y=y, width=width, height=height, style=style, **kwargs) # Setup button showing value self._default_button = UIFlatButton(text=self._value or "", width=self.width, height=self.height) self._default_button.on_click = self._on_button_click # type: ignore self._overlay = _UIDropdownOverlay() self._update_options() # add children after super class setup self.add(self._default_button) self.register_event_type("on_change") self.with_border(color=arcade.color.RED) @property def value(self) -> Optional[str]: """Current selected option.""" return self._value @value.setter def value(self, value: Optional[str]): """Change the current selected option to a new option.""" old_value = self._value self._value = value self._default_button.text = self._value or "" self._update_options() self.dispatch_event("on_change", UIOnChangeEvent(self, old_value, value)) self.trigger_render() def _update_options(self): # generate options self._overlay.clear() # is there another way then deepcopy, does it matter? ("premature optimization is the root of all evil") active_style = deepcopy(UIFlatButton.DEFAULT_STYLE) active_style["normal"]["bg"] = (55, 66, 81) for option in self._options: if option is None: # None = UIDropdown.DIVIDER, required by pyright self._overlay.add(UIWidget(width=self.width, height=2).with_background(color=arcade.color.GRAY)) continue else: button = self._overlay.add( UIFlatButton( text=option, width=self.width, height=self.height, style=active_style if self.value == option else UIFlatButton.DEFAULT_STYLE, ) ) button.on_click = self._on_option_click def _find_ui_manager(self): # search tree for UIManager parent = self.parent while isinstance(parent, UIWidget): # parent = parent.parent return parent if isinstance(parent, UIManager) else None def _show_overlay(self): manager = self._find_ui_manager() if manager is None: raise Exception("UIDropdown could not find UIManager in its parents.") self._overlay.show(manager) def _on_button_click(self, _: UIOnClickEvent): self._show_overlay() def _on_option_click(self, event: UIOnClickEvent): source: UIFlatButton = event.source self.value = source.text self._overlay.hide()
[docs] def do_layout(self): self._default_button.rect = self.rect # resize layout to contain widgets overlay = self._overlay rect = overlay.rect if overlay.size_hint_min is not None: rect = rect.resize(*overlay.size_hint_min) self._overlay.rect = rect.align_top(self.bottom - 2).align_left(self._default_button.left)
[docs] def on_change(self, event: UIOnChangeEvent): """To be implemented by the user, triggered when the current selected value is changed to a different option.""" pass