Source code for pyface.i_widget
# (C) Copyright 2005-2022 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
""" The base interface for all pyface widgets. """
from traits.api import Any, Bool, HasTraits, Interface, Instance, Str
[docs]class IWidget(Interface):
""" The base interface for all pyface widgets.
Pyface widgets delegate to a toolkit specific control.
"""
#: The toolkit specific control that represents the widget.
control = Any()
#: The control's optional parent control.
parent = Any()
#: Whether or not the control is visible
visible = Bool(True)
#: Whether or not the control is enabled
enabled = Bool(True)
#: A tooltip for the widget.
tooltip = Str()
#: An optional context menu for the widget.
context_menu = Instance("pyface.action.menu_manager.MenuManager")
# ------------------------------------------------------------------------
# 'IWidget' interface.
# ------------------------------------------------------------------------
[docs] def show(self, visible):
""" Show or hide the widget.
Parameters
----------
visible : bool
Visible should be ``True`` if the widget should be shown.
"""
[docs] def enable(self, enabled):
""" Enable or disable the widget.
Parameters
----------
enabled : bool
The enabled state to set the widget to.
"""
[docs] def has_focus(self):
""" Does the widget currently have keyboard focus?
Returns
-------
focus_state : bool
Whether or not the widget has keyboard focus.
"""
[docs] def create(self):
""" Creates the toolkit specific control.
This method should create the control and assign it to the
:py:attr:``control`` trait.
"""
# ------------------------------------------------------------------------
# Protected 'IWidget' interface.
# ------------------------------------------------------------------------
def _create_control(self, parent):
""" Create toolkit specific control that represents the widget.
Parameters
----------
parent : toolkit control
The toolkit control to be used as the parent for the widget's
control.
Returns
-------
control : toolkit control
A control for the widget.
"""
def _add_event_listeners(self):
""" Set up toolkit-specific bindings for events """
def _remove_event_listeners(self):
""" Remove toolkit-specific bindings for events """
[docs]class MWidget(HasTraits):
""" The mixin class that contains common code for toolkit specific
implementations of the IWidget interface.
"""
#: A tooltip for the widget.
tooltip = Str()
#: An optional context menu for the widget.
context_menu = Instance("pyface.action.menu_manager.MenuManager")
[docs] def create(self):
""" Creates the toolkit specific control.
The default implementation simply calls _create()
"""
self._create()
[docs] def destroy(self):
""" Call clean-up code and destroy toolkit objects.
Subclasses should override to perform any additional clean-up, ensuring
that they call super() after that clean-up.
"""
if self.control is not None:
self._remove_event_listeners()
self.control = None
# ------------------------------------------------------------------------
# Protected 'IWidget' interface.
# ------------------------------------------------------------------------
def _create(self):
""" Creates the toolkit specific control.
This method should create the control and assign it to the
:py:attr:``control`` trait.
"""
self.control = self._create_control(self.parent)
self._initialize_control()
self._add_event_listeners()
def _create_control(self, parent):
""" Create toolkit specific control that represents the widget.
Parameters
----------
parent : toolkit control
The toolkit control to be used as the parent for the widget's
control.
Returns
-------
control : toolkit control
A control for the widget.
"""
raise NotImplementedError()
def _initialize_control(self):
""" Perform any post-creation initialization for the control.
"""
self._set_control_tooltip(self.tooltip)
def _add_event_listeners(self):
""" Set up toolkit-specific bindings for events """
self.observe(self._tooltip_updated, "tooltip", dispatch="ui")
self.observe(
self._context_menu_updated, "context_menu", dispatch="ui"
)
if self.control is not None and self.context_menu is not None:
self._observe_control_context_menu()
def _remove_event_listeners(self):
""" Remove toolkit-specific bindings for events """
if self.control is not None and self.context_menu is not None:
self._observe_control_context_menu(remove=True)
self.observe(
self._context_menu_updated,
"context_menu",
dispatch="ui",
remove=True,
)
self.observe(
self._tooltip_updated, "tooltip", dispatch="ui", remove=True
)
# Toolkit control interface ---------------------------------------------
def _get_control_tooltip(self):
""" Toolkit specific method to get the control's tooltip. """
raise NotImplementedError()
def _set_control_tooltip(self, tooltip):
""" Toolkit specific method to set the control's tooltip. """
raise NotImplementedError()
def _observe_control_context_menu(self, remove=False):
""" Toolkit specific method to change the context menu observer.
This should use _handle_control_context_menu as the event handler.
Parameters
----------
remove : bool
Whether the context menu handler should be removed or added.
"""
raise NotImplementedError()
def _handle_control_context_menu(self, event):
""" Handle a context menu event.
Implementations should override this with a method suitable to be used
as a toolkit event handler that invokes a context menu.
The function signature will likely vary from toolkit to toolkit.
"""
raise NotImplementedError()
# Trait change handlers -------------------------------------------------
def _tooltip_updated(self, event):
tooltip = event.new
if self.control is not None:
self._set_control_tooltip(tooltip)
def _context_menu_updated(self, event):
if self.control is not None:
if event.new is None:
self._observe_control_context_menu(remove=True)
if event.old is None:
self._observe_control_context_menu()
