Source code for ipywidgets.widgets.widget_selectioncontainer
# Copyright (c) Jupyter Development Team.
# Distributed under the terms of the Modified BSD License.
"""SelectionContainer class.
Represents a multipage container that can be used to group other widgets into
pages.
"""
from .widget_box import Box
from .widget import register
from .widget_core import CoreWidget
from traitlets import Unicode, Dict, CInt, TraitError, validate, observe
from .trait_types import TypedTuple
from itertools import chain, repeat, islice
# Inspired by an itertools recipe: https://docs.python.org/3/library/itertools.html#itertools-recipes
[docs]def pad(iterable, padding=None, length=None):
"""Returns the sequence elements and then returns None up to the given size (or indefinitely if size is None)."""
return islice(chain(iterable, repeat(padding)), length)
class _SelectionContainer(Box, CoreWidget):
"""Base class used to display multiple child widgets."""
titles = TypedTuple(trait=Unicode(), help="Titles of the pages").tag(sync=True)
selected_index = CInt(
help="""The index of the selected page. This is either an integer selecting a particular sub-widget, or None to have no widgets selected.""",
allow_none=True,
default_value=None
).tag(sync=True)
@validate('selected_index')
def _validated_index(self, proposal):
if proposal.value is None or 0 <= proposal.value < len(self.children):
return proposal.value
else:
raise TraitError('Invalid selection: index out of bounds')
@validate('titles')
def _validate_titles(self, proposal):
return tuple(pad(proposal.value, '', len(self.children)))
@observe('children')
def _observe_children(self, change):
self._reset_selected_index()
self._reset_titles()
def _reset_selected_index(self):
if self.selected_index is not None and len(self.children) < self.selected_index:
self.selected_index = None
def _reset_titles(self):
if len(self.titles) != len(self.children):
# Run validation function
self.titles = tuple(self.titles)
def set_title(self, index, title):
"""Sets the title of a container page.
Parameters
----------
index : int
Index of the container page
title : unicode
New title
"""
titles = list(self.titles)
# for backwards compatibility with ipywidgets 7.x
if title is None:
title = ''
titles[index]=title
self.titles = tuple(titles)
def get_title(self, index):
"""Gets the title of a container page.
Parameters
----------
index : int
Index of the container page
"""
return self.titles[index]
[docs]@register
class Accordion(_SelectionContainer):
"""Displays children each on a separate accordion page."""
_view_name = Unicode('AccordionView').tag(sync=True)
_model_name = Unicode('AccordionModel').tag(sync=True)
[docs]@register
class Tab(_SelectionContainer):
"""Displays children each on a separate accordion tab."""
_view_name = Unicode('TabView').tag(sync=True)
_model_name = Unicode('TabModel').tag(sync=True)
[docs] def __init__(self, children=(), **kwargs):
if len(children) > 0 and 'selected_index' not in kwargs:
kwargs['selected_index'] = 0
super().__init__(children=children, **kwargs)
def _reset_selected_index(self):
# if there are no tabs, then none should be selected
num_children = len(self.children)
if num_children == 0:
self.selected_index = None
# if there are tabs, but none is selected, select the first one
elif self.selected_index == None:
self.selected_index = 0
# if there are tabs and a selection, but the selection is no longer
# valid, select the last tab.
elif num_children < self.selected_index:
self.selected_index = num_children - 1
[docs]@register
class Stack(_SelectionContainer):
"""Displays only the selected child."""
_view_name = Unicode('StackView').tag(sync=True)
_model_name = Unicode('StackModel').tag(sync=True)