'''
Behaviors
=========
.. versionadded:: 1.8.0
This module implements behaviors that can be mixed with existing base widgets.
For example, if you want to add a "button" capability to an `Image`, you could
do::
class IconButton(ButtonBehavior, Image):
pass
.. note::
The behavior class must always be _before_ the widget class. If you don't
specify the inheritance in this order, the behavior will not work.
'''
__all__ = ('ButtonBehavior', 'ToggleButtonBehavior', 'DragBehavior',
'FocusBehavior', 'CompoundSelectionBehavior')
from kivy.clock import Clock
from kivy.properties import OptionProperty, ObjectProperty, NumericProperty,\
ReferenceListProperty, BooleanProperty, ListProperty, AliasProperty
from kivy.config import Config
from kivy.metrics import sp
from kivy.base import EventLoop
from kivy.logger import Logger
from functools import partial
from weakref import ref
from time import clock, time
import string
# When we are generating documentation, Config doesn't exist
_scroll_timeout = _scroll_distance = 0
_is_desktop = False
_keyboard_mode = 'system'
if Config:
_scroll_timeout = Config.getint('widgets', 'scroll_timeout')
_scroll_distance = Config.getint('widgets', 'scroll_distance')
_is_desktop = Config.getboolean('kivy', 'desktop')
_keyboard_mode = Config.get('kivy', 'keyboard_mode')
[docs]class DragBehavior(object):
'''Drag behavior. When combined with a widget, dragging in the rectangle
defined by :attr:`drag_rectangle` will drag the widget.
For example, to make a popup which is draggable by its title do::
from kivy.uix.behaviors import DragBehavior
from kivy.uix.popup import Popup
class DragPopup(DragBehavior, Popup):
pass
And in .kv do::
<DragPopup>:
drag_rectangle: self.x, self.y+self._container.height, self.width,\
self.height - self._container.height
drag_timeout: 10000000
drag_distance: 0
.. versionadded:: 1.8.0
'''
drag_distance = NumericProperty(_scroll_distance)
'''Distance to move before dragging the :class:`DragBehavior`, in pixels.
As soon as the distance has been traveled, the :class:`DragBehavior` will
start to drag, and no touch event will go to children.
It is advisable that you base this value on the dpi of your target device's
screen.
:attr:`drag_distance` is a :class:`~kivy.properties.NumericProperty`,
defaults to 20 (pixels), according to the default value of scroll_distance
in user configuration.
'''
drag_timeout = NumericProperty(_scroll_timeout)
'''Timeout allowed to trigger the :attr:`drag_distance`, in milliseconds.
If the user has not moved :attr:`drag_distance` within the timeout,
dragging will be disabled, and the touch event will go to the children.
:attr:`drag_timeout` is a :class:`~kivy.properties.NumericProperty`,
defaults to 55 (milliseconds), according to the default value of
scroll_timeout in user configuration.
'''
drag_rect_x = NumericProperty(0)
'''X position of the axis aligned bounding rectangle where dragging
is allowed. In window coordinates.
:attr:`drag_rect_x` is a :class:`~kivy.properties.NumericProperty`,
defaults to 0.
'''
drag_rect_y = NumericProperty(0)
'''Y position of the axis aligned bounding rectangle where dragging
is allowed. In window coordinates.
:attr:`drag_rect_Y` is a :class:`~kivy.properties.NumericProperty`,
defaults to 0.
'''
drag_rect_width = NumericProperty(100)
'''Width of the axis aligned bounding rectangle where dragging is allowed.
:attr:`drag_rect_width` is a :class:`~kivy.properties.NumericProperty`,
defaults to 100.
'''
drag_rect_height = NumericProperty(100)
'''Height of the axis aligned bounding rectangle where dragging is allowed.
:attr:`drag_rect_height` is a :class:`~kivy.properties.NumericProperty`,
defaults to 100.
'''
drag_rectangle = ReferenceListProperty(drag_rect_x, drag_rect_y,
drag_rect_width, drag_rect_height)
'''Position and size of the axis aligned bounding rectangle where dragging
is allowed.
:attr:`drag_rectangle` is a :class:`~kivy.properties.ReferenceListProperty`
of (:attr:`drag_rect_x`, :attr:`drag_rect_y`, :attr:`drag_rect_width`,
:attr:`drag_rect_height`) properties.
'''
def __init__(self, **kwargs):
self._drag_touch = None
super(DragBehavior, self).__init__(**kwargs)
def _get_uid(self, prefix='sv'):
return '{0}.{1}'.format(prefix, self.uid)
def on_touch_down(self, touch):
xx, yy, w, h = self.drag_rectangle
x, y = touch.pos
if not self.collide_point(x, y):
touch.ud[self._get_uid('svavoid')] = True
return super(DragBehavior, self).on_touch_down(touch)
if self._drag_touch or ('button' in touch.profile and
touch.button.startswith('scroll')) or\
not ((xx < x <= xx + w) and (yy < y <= yy + h)):
return super(DragBehavior, self).on_touch_down(touch)
# no mouse scrolling, so the user is going to drag with this touch.
self._drag_touch = touch
uid = self._get_uid()
touch.grab(self)
touch.ud[uid] = {
'mode': 'unknown',
'dx': 0,
'dy': 0}
Clock.schedule_once(self._change_touch_mode,
self.drag_timeout / 1000.)
return True
def on_touch_move(self, touch):
if self._get_uid('svavoid') in touch.ud or\
self._drag_touch is not touch:
return super(DragBehavior, self).on_touch_move(touch) or\
self._get_uid() in touch.ud
if touch.grab_current is not self:
return True
uid = self._get_uid()
ud = touch.ud[uid]
mode = ud['mode']
if mode == 'unknown':
ud['dx'] += abs(touch.dx)
ud['dy'] += abs(touch.dy)
if ud['dx'] > sp(self.drag_distance):
mode = 'drag'
if ud['dy'] > sp(self.drag_distance):
mode = 'drag'
ud['mode'] = mode
if mode == 'drag':
self.x += touch.dx
self.y += touch.dy
return True
def on_touch_up(self, touch):
if self._get_uid('svavoid') in touch.ud:
return super(DragBehavior, self).on_touch_up(touch)
if self._drag_touch and self in [x() for x in touch.grab_list]:
touch.ungrab(self)
self._drag_touch = None
ud = touch.ud[self._get_uid()]
if ud['mode'] == 'unknown':
super(DragBehavior, self).on_touch_down(touch)
Clock.schedule_once(partial(self._do_touch_up, touch), .1)
else:
if self._drag_touch is not touch:
super(DragBehavior, self).on_touch_up(touch)
return self._get_uid() in touch.ud
def _do_touch_up(self, touch, *largs):
super(DragBehavior, self).on_touch_up(touch)
# don't forget about grab event!
for x in touch.grab_list[:]:
touch.grab_list.remove(x)
x = x()
if not x:
continue
touch.grab_current = x
super(DragBehavior, self).on_touch_up(touch)
touch.grab_current = None
def _change_touch_mode(self, *largs):
if not self._drag_touch:
return
uid = self._get_uid()
touch = self._drag_touch
ud = touch.ud[uid]
if ud['mode'] != 'unknown':
return
touch.ungrab(self)
self._drag_touch = None
super(DragBehavior, self).on_touch_down(touch)
return
[docs]class FocusBehavior(object):
'''Implements keyboard focus behavior. When combined with other
FocusBehavior widgets it allows one to cycle focus among them by pressing
tab. In addition, upon gaining focus the instance will automatically
receive keyboard input.
Focus, very different then selection, is intimately tied with the keyboard;
each keyboard can focus on zero or one widgets, and each widget can only
have the focus of one keyboard. However, multiple keyboards can focus
simultaneously on different widgets. When escape is hit, the widget having
the focus of that keyboard will de-focus.
In essence, focus is implemented as a doubly linked list, where each
node holds a (weak) reference to the instance before it and after it,
as visualized when cycling through the nodes using tab (forward) or
shift+tab (backward). If previous or next widget is not specified,
:attr:`focus_next` and :attr:`focus_previous` default to `None`,
which means that the children list and parents are walked to find
the next focusable widget, unless :attr:`focus_next` or
:attr:`focus_previous` is set to the `StopIteration` class, in which case
focus stops there.
For example, to cycle focus between :class:`~kivy.uix.button.Button`
elements of a :class:`~kivy.uix.gridlayout.GridLayout`::
class FocusButton(FocusBehavior, Button):
pass
grid = GridLayout(cols=4)
for i in range(40):
grid.add_widget(FocusButton(text=str(i)))
# clicking on a widget will activate focus, and tab can now be used
# to cycle through
.. versionadded:: 1.9.0
.. warning::
This code is still experimental, and its API is subject to change in a
future version.
'''
_focus_win = None
_requested_keyboard = False
_keyboard = ObjectProperty(None, allownone=True)
_keyboards = {}
ignored_touch = []
'''A list of touches that should not be used to defocus. After on_touch_up,
every touch that is not in :attr:`ignored_touch` will defocus all the
focused widgets, if, the config keyboard mode is not multi. Touches on
focusable widgets that were used to focus are automatically added here.
Example usage::
class Unfocusable(Widget):
def on_touch_down(self, touch):
if self.collide_point(*touch.pos):
FocusBehavior.ignored_touch.append(touch)
Notice that you need to access this as class, not instance variable.
'''
def _set_keyboard(self, value):
focused = self.focused
keyboard = self._keyboard
keyboards = FocusBehavior._keyboards
if keyboard:
self.focused = False # this'll unbind
if self._keyboard: # remove assigned keyboard from dict
del keyboards[keyboard]
if value and not value in keyboards:
keyboards[value] = None
self._keyboard = value
self.focused = focused
def _get_keyboard(self):
return self._keyboard
keyboard = AliasProperty(_get_keyboard, _set_keyboard,
bind=('_keyboard', ))
'''The keyboard to bind, or bound to the widget when focused.
When None, a keyboard is requested and released whenever the widget comes
into and out of focus. If not None, it must be a keyboard, which gets
bound and unbound from the widget whenever it's in or out of focus. It is
useful only when more than one keyboard is available, so it is recommended
to be set to None when only one keyboard is available
If more than one keyboard is available, whenever an instance get focused
a new keyboard will be requested if None. Unless, the other instances lose
focus (e.g. if tab was used), a new keyboard will appear. When this is
undesired, the keyboard property can be used. For example, if there are
two users with two keyboards, then each keyboard can be assigned to
different groups of instances of FocusBehavior, ensuring that within
each group, only one FocusBehavior will have focus, and will receive input
from the correct keyboard. see `keyboard_mode` in :mod:`~kivy.config` for
information on the keyboard modes.
:attr:`keyboard` is a :class:`~kivy.properties.AliasProperty`, defaults to
None.
.. note::
When Config's `keyboard_mode` is multi, each new touch is considered
a touch by a different user and will focus (if clicked on a
focusable) with a new keyboard. Already focused elements will not lose
their focus (even if clicked on a unfocusable).
.. note:
If the keyboard property is set, that keyboard will be used when the
instance gets focused. If widgets with different keyboards are linked
through :attr:`focus_next` and :attr:`focus_previous`, then as they are
tabbed through, different keyboards will become active. Therefore,
typically it's undesirable to link instances which are assigned
different keyboards.
.. note:
When an instance has focus, setting keyboard to None will remove the
current keyboard, but will then try to get a keyboard back. It is
better to set :attr:`focused` to False.
.. warning:
When assigning a keyboard, the keyboard must not be released while
it is still assigned to an instance. Similarly, the keyboard created
by the instance on focus and assigned to :attr:`keyboard` if None,
will be released by the instance when the instance loses focus.
Therefore, it is not safe to assign this keyboard to another instance's
:attr:`keyboard`.
'''
is_focusable = BooleanProperty(_is_desktop)
'''Whether the instance can become focused. If focused, it'll lose focus
when set to False.
:attr:`is_focusable` is a :class:`~kivy.properties.BooleanProperty`,
defaults to True on a desktop (i.e. desktop is True in
:mod:`~kivy.config`), False otherwise.
'''
focused = BooleanProperty(False)
'''Whether the instance currently has focus.
Setting it to True, will bind to and/or request the keyboard, and input
will be forwarded to the instance. Setting it to False, will unbind
and/or release the keyboard. For a given keyboard, only one widget can
have its focus, so focusing one will automatically unfocus the other
instance holding its focus.
:attr:`focused` is a :class:`~kivy.properties.BooleanProperty`, defaults to
False.
'''
def _set_on_focus_next(self, instance, value):
''' If changing code, ensure following code is not infinite loop:
widget.focus_next = widget
widget.focus_previous = widget
widget.focus_previous = widget2
'''
next = self._old_focus_next
if next is value: # prevent infinite loop
return
if isinstance(next, FocusBehavior):
next.focus_previous = None
self._old_focus_next = value
if value is None or value is StopIteration:
return
if not isinstance(value, FocusBehavior):
raise ValueError('focus_next accepts only objects based'
' on FocusBehavior, or the StopIteration class.')
value.focus_previous = self
focus_next = ObjectProperty(None, allownone=True)
'''The :class:`FocusBehavior` instance to acquire focus when
tab is pressed when this instance has focus, if not `None` or
`'StopIteration'`.
When tab is pressed, focus cycles through all the :class:`FocusBehavior`
widgets that are linked through :attr:`focus_next` and are focusable. If
:attr:`focus_next` is `None`, it instead walks the children lists to find
the next focusable widget. Finally, if :attr:`focus_next` is
the `StopIteration` class, focus won't move forward, but end here.
.. note:
Setting :attr:`focus_next` automatically sets :attr:`focus_previous`
of the other instance to point to this instance, if not None or
`StopIteration`. Similarly, if it wasn't None or `StopIteration`, it
also sets the :attr:`focus_previous` property of the instance
previously in :attr:`focus_next` to `None`. Therefore, it is only
required to set one side of the :attr:`focus_previous`,
:attr:`focus_next`, links since the other side will be set
automatically.
:attr:`focus_next` is a :class:`~kivy.properties.ObjectProperty`, defaults
to `None`.
'''
def _set_on_focus_previous(self, instance, value):
prev = self._old_focus_previous
if prev is value:
return
if isinstance(prev, FocusBehavior):
prev.focus_next = None
self._old_focus_previous = value
if value is None or value is StopIteration:
return
if not isinstance(value, FocusBehavior):
raise ValueError('focus_previous accepts only objects based'
' on FocusBehavior, or the StopIteration class.')
value.focus_next = self
focus_previous = ObjectProperty(None, allownone=True)
'''The :class:`FocusBehavior` instance to acquire focus when
shift+tab is pressed on this instance, if not None or `StopIteration`.
When shift+tab is pressed, focus cycles through all the
:class:`FocusBehavior` widgets that are linked through
:attr:`focus_previous` and are focusable. If :attr:`focus_previous` is
`None', it instead walks the children tree to find the
previous focusable widget. Finally, if :attr:`focus_previous` is the
`StopIteration` class, focus won't move backward, but end here.
.. note:
Setting :attr:`focus_previous` automatically sets :attr:`focus_next`
of the other instance to point to this instance, if not None or
`StopIteration`. Similarly, if it wasn't None or `StopIteration`, it
also sets the :attr:`focus_next` property of the instance previously in
:attr:`focus_previous` to `None`. Therefore, it is only required
to set one side of the :attr:`focus_previous`, :attr:`focus_next`,
links since the other side will be set automatically.
:attr:`focus_previous` is a :class:`~kivy.properties.ObjectProperty`,
defaults to `None`.
'''
keyboard_mode = OptionProperty('auto', options=('auto', 'managed'))
'''How the keyboard visibility should be managed (auto will have standard
behaviour to show/hide on focus, managed requires setting keyboard_visible
manually, or calling the helper functions ``show_keyboard()``
and ``hide_keyboard()``.
:attr:`keyboard_mode` is an :class:`~kivy.properties.OptionsProperty` and
defaults to 'auto'. Can be one of 'auto' or 'managed'.
'''
input_type = OptionProperty('text', options=('text', 'number', 'url',
'mail', 'datetime', 'tel',
'address'))
'''The kind of input keyboard to request.
.. versionadded:: 1.8.0
:attr:`input_type` is an :class:`~kivy.properties.OptionsProperty` and
defaults to 'text'. Can be one of 'text', 'number', 'url', 'mail',
'datetime', 'tel', 'address'.
'''
unfocus_on_touch = BooleanProperty(_keyboard_mode not in
('multi', 'systemandmulti'))
'''Whether a instance should lose focus when clicked outside the instance.
When a user clicks on a widget that is focus aware and shares the same
keyboard as the this widget (which in the case of only one keyboard, are
all focus aware widgets), then as the other widgets gains focus, this
widget loses focus. In addition to that, if this property is `True`,
clicking on any widget other than this widget, will remove focus form this
widget.
:attr:`unfocus_on_touch` is a :class:`~kivy.properties.BooleanProperty`,
defaults to `False` if the `keyboard_mode` in :attr:`~kivy.config.Config`
is `'multi'` or `'systemandmulti'`, otherwise it defaults to `True`.
'''
def __init__(self, **kwargs):
self._old_focus_next = None
self._old_focus_previous = None
super(FocusBehavior, self).__init__(**kwargs)
self._keyboard_mode = _keyboard_mode
self.bind(focused=self._on_focused, disabled=self._on_focusable,
is_focusable=self._on_focusable,
focus_next=self._set_on_focus_next,
focus_previous=self._set_on_focus_previous)
def _on_focusable(self, instance, value):
if self.disabled or not self.is_focusable:
self.focused = False
def _on_focused(self, instance, value, *largs):
if self.keyboard_mode == 'auto':
if value:
self._bind_keyboard()
else:
self._unbind_keyboard()
def _ensure_keyboard(self):
if self._keyboard is None:
win = self._focus_win
if not win:
self._focus_win = win = EventLoop.window
if not win:
Logger.warning('FocusBehavior: '
'Cannot focus the element, unable to get root window')
return
self._requested_keyboard = True
keyboard = self._keyboard =\
win.request_keyboard(self._keyboard_released, self,
input_type=self.input_type)
keyboards = FocusBehavior._keyboards
if keyboard not in keyboards:
keyboards[keyboard] = None
def _bind_keyboard(self):
self._ensure_keyboard()
keyboard = self._keyboard
if not keyboard or self.disabled or not self.is_focusable:
self.focused = False
return
keyboards = FocusBehavior._keyboards
old_focus = keyboards[keyboard] # keyboard should be in dict
if old_focus:
old_focus.focused = False
# keyboard shouldn't have been released here, see keyboard warning
keyboards[keyboard] = self
keyboard.bind(on_key_down=self.keyboard_on_key_down,
on_key_up=self.keyboard_on_key_up)
def _unbind_keyboard(self):
keyboard = self._keyboard
if keyboard:
keyboard.unbind(on_key_down=self.keyboard_on_key_down,
on_key_up=self.keyboard_on_key_up)
if self._requested_keyboard:
keyboard.release()
self._keyboard = None
self._requested_keyboard = False
del FocusBehavior._keyboards[keyboard]
else:
FocusBehavior._keyboards[keyboard] = None
def _keyboard_released(self):
self.focused = False
def on_touch_down(self, touch):
if not self.collide_point(*touch.pos):
return
if (not self.disabled and self.is_focusable and
('button' not in touch.profile or
not touch.button.startswith('scroll'))):
self.focused = True
FocusBehavior.ignored_touch.append(touch)
return super(FocusBehavior, self).on_touch_down(touch)
@staticmethod
def _handle_post_on_touch_up(touch):
''' Called by window after each touch has finished.
'''
touches = FocusBehavior.ignored_touch
if touch in touches:
touches.remove(touch)
return
for focusable in list(FocusBehavior._keyboards.values()):
if focusable is None or not focusable.unfocus_on_touch:
continue
focusable.focused = False
def _get_focus_next(self, focus_dir):
current = self
walk_tree = 'walk' if focus_dir is 'focus_next' else 'walk_reverse'
while 1:
# if we hit a focusable, walk through focus_xxx
while getattr(current, focus_dir) is not None:
current = getattr(current, focus_dir)
if current is self or current is StopIteration:
return None # make sure we don't loop forever
if current.is_focusable and not current.disabled:
return current
# hit unfocusable, walk widget tree
itr = getattr(current, walk_tree)(loopback=True)
if focus_dir is 'focus_next':
next(itr) # current is returned first when walking forward
for current in itr:
if isinstance(current, FocusBehavior):
break
# why did we stop
if isinstance(current, FocusBehavior):
if current is self:
return None
if current.is_focusable and not current.disabled:
return current
else:
return None
[docs] def keyboard_on_key_down(self, window, keycode, text, modifiers):
'''The method bound to the keyboard when the instance has focus.
When the instance becomes focused, this method is bound to the
keyboard and will be called for every input press. The parameters are
the same as :meth:`kivy.core.window.WindowBase.on_key_down`.
When overwriting the method in the derived widget, super should be
called to enable tab cycling. If the derived widget wishes to use tab
for its own purposes, it can call super at the end after it is done if
it didn't consume tab.
Similar to other keyboard functions, it should return True if the
key was consumed.
'''
if keycode[1] == 'tab': # deal with cycle
if ['shift'] == modifiers:
next = self._get_focus_next('focus_previous')
else:
next = self._get_focus_next('focus_next')
if next:
self.focused = False
def _fn(dt):
next.focused = True
Clock.schedule_once(_fn)
return True
return False
[docs] def keyboard_on_key_up(self, window, keycode):
'''The method bound to the keyboard when the instance has focus.
When the instance becomes focused, this method is bound to the
keyboard and will be called for every input release. The parameters are
the same as :meth:`kivy.core.window.WindowBase.on_key_up`.
When overwriting the method in the derived widget, super should be
called to enable de-focusing on escape. If the derived widget wishes
to use escape for its own purposes, it can call super at the end after
it is done if it didn't consume escape.
See :meth:`on_key_down`
'''
if keycode[1] == 'escape':
self.focused = False
return True
return False
[docs] def show_keyboard(self):
'''
Convenience function to show the keyboard in managed mode.
'''
if self.keyboard_mode == 'managed':
self._bind_keyboard()
[docs] def hide_keyboard(self):
'''
Convenience function to hide the keyboard in managed mode.
'''
if self.keyboard_mode == 'managed':
self._unbind_keyboard()
[docs]class CompoundSelectionBehavior(object):
'''Selection behavior implements the logic behind keyboard and touch
selection of selectable widgets managed by the derived widget.
For example, it could be combined with a
:class:`~kivy.uix.gridlayout.GridLayout` to add selection to the layout.
At its core, it keeps a dynamic list of widgets that can be selected.
Then, as the touches and keyboard input are passed in, it selects one or
more of the widgets based on these inputs. For example, it uses the mouse
scroll and keyboard up/down buttons to scroll through the list of widgets.
Multiselection can also be achieved using the keyboard shift and ctrl keys.
Finally, in addition to the up/down type keyboard inputs, it can also
accepts letters from the kayboard to be used to select nodes with
associated strings that start with those letters, similar to how files
are selected by a file browser.
When the controller needs to select a node it calls :meth:`select_node` and
:meth:`deselect_node`. Therefore, they must be overwritten in order affect
the selected nodes. By default, the class doesn't listen to keyboard and
touch events, therefore, the derived widget must call
:meth:`select_with_touch`, :meth:`select_with_key_down`, and
:meth:`select_with_key_up` on events that it wants to pass on for selection
purposes.
For example, to add selection to a grid layout which will contain
:class:`~kivy.uix.Button` widgets::
class SelectableGrid(CompoundSelectionBehavior, GridLayout):
def __init__(self, **kwargs):
super(CompoundSelectionBehavior, self).__init__(**kwargs)
keyboard = Window.request_keyboard(None, self)
keyboard.bind(on_key_down=self.select_with_key_down,
on_key_up=self.select_with_key_up)
def select_node(self, node):
node.background_color = (1, 0, 0, 1)
return super(CompoundSelectionBehavior, self).select_node(node)
def deselect_node(self, node):
node.background_color = (1, 1, 1, 1)
super(CompoundSelectionBehavior, self).deselect_node(node)
Then, for each button added to the layout, bind on_touch_down of the button
to :meth:`select_with_touch` to pass on the touch events.
.. versionadded:: 1.9.0
.. warning::
This code is still experimental, and its API is subject to change in a
future version.
'''
selected_nodes = ListProperty([])
'''The list of selected nodes.
.. note:
Multiple nodes can be selected right after another using e.g. the
keyboard, so when listening to :attr:`selected_nodes` one should be
aware of this.
:attr:`selected_nodes` is a :class:`~kivy.properties.ListProperty` and
defaults to the empty list, []. It is read-only and should not be modified.
'''
touch_multiselect = BooleanProperty(False)
'''A special touch mode which determines whether touch events, as
processed with :meth:`select_with_touch`, will add to the selection the
currently touched node, or if it will clear the selection before adding the
node. This allows the selection of multiple nodes by simply touching them.
This is different than :attr:`multiselect`, because when this is True
simply touching an unselected node will select it, even if e.g. ctrl is not
pressed. If this is False, however, ctrl is required to be held in order to
add to selection when :attr:`multiselect` is True.
.. note::
:attr:`multiselect`, when False, will disable
:attr:`touch_multiselect`.
:attr:`touch_multiselect` is a :class:`~kivy.properties.BooleanProperty`,
defaults to False.
'''
multiselect = BooleanProperty(False)
'''Determines whether multiple nodes can be selected. If enabled, keyboard
shift and ctrl selection, optionally combined with touch, for example, will
be able to select multiple widgets in the normally expected manner.
This dominates :attr:`touch_multiselect` when False.
:attr:`multiselect` is a :class:`~kivy.properties.BooleanProperty`
, defaults to False.
'''
keyboard_select = BooleanProperty(True)
''' Whether the keybaord can be used for selection. If False, keyboard
inputs will be ignored.
:attr:`keyboard_select` is a :class:`~kivy.properties.BooleanProperty`
, defaults to True.
'''
page_count = NumericProperty(10)
'''Determines by how much the selected node is moved up or down, relative
to position of the last selected node, when pageup (or pagedown) is
pressed.
:attr:`page_count` is a :class:`~kivy.properties.NumericProperty`,
defaults to 10.
'''
up_count = NumericProperty(1)
'''Determines by how much the selected node is moved up or down, relative
to position of the last selected node, when the up (or down) arrow on the
keyboard is pressed.
:attr:`up_count` is a :class:`~kivy.properties.NumericProperty`,
defaults to 1.
'''
right_count = NumericProperty(1)
'''Determines by how much the selected node is moved up or down, relative
to position of the last selected node, when the right (or left) arrow on
the keyboard is pressed.
:attr:`right_count` is a :class:`~kivy.properties.NumericProperty`,
defaults to 1.
'''
scroll_count = NumericProperty(0)
'''Determines by how much the selected node is moved up or down, relative
to position of the last selected node, when the mouse scroll wheel is
scrolled.
:attr:`right_count` is a :class:`~kivy.properties.NumericProperty`,
defaults to 0.
'''
_anchor = None # the last anchor node selected (e.g. shift relative node)
# the idx may be out of sync
_anchor_idx = 0 # cache indexs in case list hasn't changed
_last_selected_node = None # the absolute last node selected
_last_node_idx = 0
_ctrl_down = False # if it's pressed - for e.g. shift selection
_shift_down = False
# holds str used to find node, e.g. if word is typed. passed to goto_node
_word_filter = ''
_last_key_time = 0 # time since last press, for finding whole strs in node
_printable = set(string.printable)
_key_list = [] # keys that are already pressed, to not press continuously
_offset_counts = {} # cache of counts for faster access
def __init__(self, **kwargs):
super(CompoundSelectionBehavior, self).__init__(**kwargs)
def ensure_single_select(*l):
if (not self.multiselect) and len(self.selected_nodes) > 1:
self.clear_selection()
self._update_counts()
self.bind(multiselect=ensure_single_select,
page_count=self._update_counts, up_count=self._update_counts,
right_count=self._update_counts, scroll_count=self._update_counts)
[docs] def select_with_touch(self, node, touch=None):
'''(internal) Processes a touch on the node. This should be called by
the derived widget when a node is touched and is to be used for
selection. Depending on the keyboard keys pressed and the
configuration, it could select or deslect this and other nodes in the
selectable nodes list, :meth:`get_selectable_nodes`.
:Parameters:
`node`
The node that recieved the touch. Can be None for a scroll
type touch.
`touch`
Optionally, the touch. Defaults to None.
:Returns:
bool, True if the touch was used, False otherwise.
'''
multi = self.multiselect
multiselect = multi and (self._ctrl_down or self.touch_multiselect)
range_select = multi and self._shift_down
if touch and 'button' in touch.profile and touch.button in\
('scrollup', 'scrolldown', 'scrollleft', 'scrollright'):
node_src, idx_src = self._reslove_last_node()
node, idx = self.goto_node(touch.button, node_src, idx_src)
if node == node_src:
return False
if range_select:
self._select_range(multiselect, True, node, idx)
else:
if not multiselect:
self.clear_selection()
self.select_node(node)
return True
if node is None:
return False
if (node in self.selected_nodes and (not range_select)): # selected
if multiselect:
self.deselect_node(node)
else:
self.clear_selection()
self.select_node(node)
elif range_select:
# keep anchor only if not multislect (ctrl-type selection)
self._select_range(multiselect, not multiselect, node, 0)
else: # it's not selected at this point
if not multiselect:
self.clear_selection()
self.select_node(node)
return True
[docs] def select_with_key_down(self, keyboard, scancode, codepoint, modifiers,
**kwargs):
'''Processes a key press. This is called when a key press is to be used
for selection. Depending on the keyboard keys pressed and the
configuration, it could select or deslect nodes or node ranges
from the selectable nodes list, :meth:`get_selectable_nodes`.
The parameters are such that it could be bound directly to the
on_key_down event of a keyboard. Therefore, it is safe to be called
repeatedly when the key is held down as is done by the keyboard.
:Returns:
bool, True if the keypress was used, False otherwise.
'''
if not self.keyboard_select:
return False
keys = self._key_list
multi = self.multiselect
node_src, idx_src = self._reslove_last_node()
if scancode[1] == 'shift':
self._shift_down = True
elif scancode[1] == 'ctrl':
self._ctrl_down = True
elif (multi and 'ctrl' in modifiers and scancode[1] in ('a', 'A')
and scancode[1] not in keys):
sister_nodes = self.get_selectable_nodes()
select = self.select_node
for node in sister_nodes:
select(node)
keys.append(scancode[1])
else:
if scancode[1] in self._printable:
if clock() - self._last_key_time <= 1.:
self._word_filter += scancode[1]
else:
self._word_filter = scancode[1]
self._last_key_time = clock()
node, idx = self.goto_node(self._word_filter, node_src,
idx_src)
else:
node, idx = self.goto_node(scancode[1], node_src, idx_src)
if node == node_src:
return False
multiselect = multi and 'ctrl' in modifiers
if multi and 'shift' in modifiers:
self._select_range(multiselect, True, node, idx)
else:
if not multiselect:
self.clear_selection()
self.select_node(node)
return True
return False
[docs] def select_with_key_up(self, keyboard, scancode, **kwargs):
'''(internal) Processes a key release. This must be called by the
derived widget when a key that :meth:`select_with_key_down` returned
True is released.
The parameters are such that it could be bound directly to the
on_key_up event of a keyboard.
:Returns:
bool, True if the key release was used, False otherwise.
'''
if scancode[1] == 'shift':
self._shift_down = False
elif scancode[1] == 'ctrl':
self._ctrl_down = False
else:
try:
self._key_list.remove(scancode[1])
return True
except ValueError:
return False
return True
def _update_counts(self, *largs):
# doesn't invert indices here
pc = self.page_count
uc = self.up_count
rc = self.right_count
sc = self.scroll_count
self._offset_counts = {'pageup': -pc, 'pagedown': pc, 'up': -uc,
'down': uc, 'right': rc, 'left': -rc, 'scrollup': sc,
'scrolldown': -sc, 'scrollright': -sc, 'scrollleft': sc}
def _reslove_last_node(self):
# for offset selection, we have a anchor, and we select everything
# between anchor and added offset relative to last node
sister_nodes = self.get_selectable_nodes()
if not len(sister_nodes):
return None, 0
last_node = self._last_selected_node
last_idx = self._last_node_idx
end = len(sister_nodes) - 1
if last_node is None:
last_node = self._anchor
last_idx = self._anchor_idx
if last_node is None:
return sister_nodes[end], end
if last_idx > end or sister_nodes[last_idx] != last_node:
try:
return last_node, sister_nodes.index(last_node)
except ValueError:
return sister_nodes[end], end
return last_node, last_idx
def _select_range(self, multiselect, keep_anchor, node, idx):
'''Selects a range between self._anchor and node or idx.
If multiselect, it'll add to selection, otherwise it will unselect
everything before selecting the range. This is only called if
self.multiselect is True.
If keep anchor is False, the anchor is moved to node. This should
always be True of keyboard selection.
'''
select = self.select_node
sister_nodes = self.get_selectable_nodes()
end = len(sister_nodes) - 1
last_node = self._anchor
last_idx = self._anchor_idx
if last_node is None:
last_idx = end
last_node = sister_nodes[end]
else:
if last_idx > end or sister_nodes[last_idx] != last_node:
try:
last_idx = sister_nodes.index(last_node)
except ValueError:
# list changed - cannot do select across them
return
if idx > end or sister_nodes[idx] != node:
try: # just in case
idx = sister_nodes.index(node)
except ValueError:
return
if last_idx > idx:
last_idx, idx = idx, last_idx
if not multiselect:
self.clear_selection()
for item in sister_nodes[last_idx:idx + 1]:
select(item)
if keep_anchor:
self._anchor = last_node
self._anchor_idx = last_idx
else:
self._anchor = node # in case idx was reversed, reset
self._anchor_idx = idx
self._last_selected_node = node
self._last_node_idx = idx
[docs] def clear_selection(self):
''' Deselects all the currently selected nodes.
'''
# keep the anchor and last selected node
deselect = self.deselect_node
nodes = self.selected_nodes
# empty beforehand so lookup in deselect will be fast
self.selected_nodes = []
for node in nodes:
deselect(node)
[docs] def get_selectable_nodes(self):
'''(internal) Returns a list of the nodes that can be selected. It can
be overwritten by the derived widget to return the correct list.
This list is used to determine which nodes to select with group
selection. E.g. the last element in the list will be selected when
home is pressed, pagedown will move (or add to, if shift is held) the
selection from the current position by negative :attr:`page_count`
nodes starting from the position of the currently selected node in
this list and so on. Still, nodes can be selected even if they are not
in this list.
.. note::
It is safe to dynamically change this list including removing,
adding, or re-arranging its elements. Nodes can be selected even
if they are not on this list. And selected nodes removed from the
list will remain selected until :meth:`deselect_node` is called.
.. warning::
Layouts display their children in the reverse order. That is, the
contents of :attr:`~kivy.uix.widget.Widget.children` is displayed
form right to left, bottom to top. Therefore, internally, the
indices of the elements returned by this function is reversed to
make it work by default for most layouts so that the final result
is that e.g. home, although it will select the last element on this
list, visually it'll select the first element when counting from
top to bottom and left to right. If this behavior is not desired,
a reversed list should be returned instead.
Defaults to returning :attr:`~kivy.uix.widget.Widget.children`.
'''
return self.children
[docs] def goto_node(self, key, last_node, last_node_idx):
'''(internal) Used by the controller to get the node at the position
indicated by key. The key can be keyboard inputs, e.g. pageup,
or scroll inputs from the mouse scroll wheel, e.g. scrollup.
Last node is the last node selected and is used to find the resulting
node. For example, if the key is up, the returned node is one node
up from the last node.
It can be overwritten by the derived widget.
:Parameters:
`key`
str, the string used to find the desired node. It can be any
of the keyboard keys, as well as the mouse scrollup,
scrolldown, scrollright, and scrollleft strings. If letters
are typed in quick succession, the letters will be combined
before it's passed in as key and can be used to find nodes that
have an associated string that starts with those letters.
`last_node`
The last node that was selected.
`last_node_idx`
The cached index of the last node selected in the
:meth:`get_selectable_nodes` list. If the list hasn't changed
it saves having to look up the index of `last_node` in that
list.
:Returns:
tuple, the node targeted by key and its index in the
:meth:`get_selectable_nodes` list. Returning
`(last_node, last_node_idx)` indicates a node wasn't found.
'''
sister_nodes = self.get_selectable_nodes()
end = len(sister_nodes) - 1
counts = self._offset_counts
if end == -1:
return last_node, last_node_idx
if last_node_idx > end or sister_nodes[last_node_idx] != last_node:
try: # just in case
last_node_idx = sister_nodes.index(last_node)
except ValueError:
return last_node, last_node_idx
try:
idx = max(min(-counts[key] + last_node_idx, end), 0)
return sister_nodes[idx], idx
except KeyError:
pass
if key == 'home':
return sister_nodes[end], end
elif key == 'end':
return sister_nodes[0], 0
else:
return last_node, last_node_idx
[docs] def select_node(self, node):
''' Selects a node.
It is called by the controller when it selects a node and can be
called from the outside to select a node directly. The derived widget
should overwrite this method and change the node to its selected state
when this is called
:Parameters:
`node`
The node to be selected.
:Returns:
bool, True if the node was selected, False otherwise.
.. warning::
This method must be called by the derived widget using super if it
is overwritten.
'''
nodes = self.selected_nodes
if (not self.multiselect) and len(nodes):
self.clear_selection()
if node not in nodes:
nodes.append(node)
self._anchor = node
self._last_selected_node = node
return True
[docs] def deselect_node(self, node):
''' Deselects a possibly selected node.
It is called by the controller when it deselects a node and can also
be called from the outside to deselect a node directly. The derived
widget should overwrite this method and change the node to its
unselected state when this is called
:Parameters:
`node`
The node to be deselected.
.. warning::
This method must be called by the derived widget using super if it
is overwritten.
'''
try:
self.selected_nodes.remove(node)
except ValueError:
pass