class CrossSelect(SelectMultiple):
"""
CrossSelect provides a two-tab multi-selection widget with regex
text filtering. Items can be transferred with buttons between the
selected and unselected options.
"""
def __init__(self, *args, **kwargs):
# Compute selected and unselected values
options = kwargs.get('options', {})
if isinstance(options, list):
options = named_objs([(opt, opt) for opt in options])
self._reverse_lookup = {v: k for k, v in options.items()}
selected = [self._reverse_lookup[v] for v in kwargs.get('value', [])]
unselected = [k for k in options if k not in selected]
# Define whitelist and blacklist
self._lists = {
False: SelectMultiple(options=unselected),
True: SelectMultiple(options=selected)
}
self._lists[False].observe(self._update_selection, 'value')
self._lists[True].observe(self._update_selection, 'value')
# Define buttons
button_layout = Layout(width='50px')
self._buttons = {
False: Button(description='<<', layout=button_layout),
True: Button(description='>>', layout=button_layout)
}
self._buttons[False].on_click(self._apply_selection)
self._buttons[True].on_click(self._apply_selection)
# Define search
self._search = {
False: Text(placeholder='Filter available options'),
True: Text(placeholder='Filter selected options')
}
self._search[False].observe(self._filter_options, 'value')
self._search[True].observe(self._filter_options, 'value')
# Define Layout
no_margin = Layout(margin='0')
row_layout = Layout(margin='0',
display='flex',
justify_content='space-between')
search_row = HBox([self._search[False], self._search[True]])
search_row.layout = row_layout
button_box = VBox([self._buttons[True], self._buttons[False]],
layout=Layout(margin='auto 0'))
tab_row = HBox([self._lists[False], button_box, self._lists[True]])
tab_row.layout = row_layout
self._composite = VBox([search_row, tab_row], layout=no_margin)
self.observe(self._update_options, 'options')
self.observe(self._update_value, 'value')
self._selected = {False: [], True: []}
self._query = {False: '', True: ''}
super(CrossSelect, self).__init__(*args, **dict(kwargs,
options=options))
def _update_value(self, event):
selected = [self._reverse_lookup.get(v, v) for v in event['new']]
self._lists[True].options = selected
self._lists[True].value = []
self._lists[False].options = [
o for o in self.options if o not in selected
]
def _update_options(self, event):
"""
Updates the options of each of the sublists after the options
for the whole widget are updated.
"""
self._reverse_lookup = {v: k for k, v in event['new'].items()}
options = list(event['new'].keys()) if isinstance(
event, dict) else event['new']
self._selected[False] = []
self._selected[True] = []
self._lists[True].options = ['']
self._lists[True].value = []
self._lists[False].options = options
self._lists[False].value = []
self._apply_filters()
def _apply_filters(self):
self._filter_options({'owner': self._search[False]})
self._filter_options({'owner': self._search[True]})
def _filter_options(self, event):
"""
Filters unselected options based on a text query event.
"""
selected = event['owner'] is self._search[True]
query = self._query[selected] if 'new' not in event else event['new']
self._query[selected] = query
other = self._lists[not selected].options
options = [o for o in self.options if o not in other]
if not query:
self._lists[selected].options = options
self._lists[selected].value = []
else:
try:
match = re.compile(query)
matches = list(filter(match.search, options))
options = matches + [
opt for opt in options if opt not in matches
]
except:
matches = options
self._lists[selected].options = options if options else ['']
self._lists[selected].value = matches
def _update_selection(self, event):
"""
Updates the current selection in each list.
"""
selected = event['owner'] is self._lists[True]
self._selected[selected] = [v for v in event['new'] if v != '']
def _apply_selection(self, event):
"""
Applies the current selection depending on which button was
pressed.
"""
selected = event is self._buttons[True]
new = self._selected[not selected]
old = self._lists[selected].options
other = self._lists[not selected].options
merged = sorted([v for v in list(old) + list(new) if v != ''])
leftovers = sorted([o for o in other if o not in new and o != ''])
new_values = merged if selected else leftovers
self._lists[selected].options = merged if merged else ['']
self._lists[not selected].options = leftovers if leftovers else ['']
self.value = [
self._options_dict[o] for o in self._lists[True].options if o != ''
]
self._apply_filters()
def _ipython_display_(self, **kwargs):
"""
Displays the composite widget.
"""
self._composite._ipython_display_(**kwargs)
def get_state(self, key=None, drop_defaults=False):
# HACK: Lets this composite widget pretend to be a regular widget
# when included into a layout.
if key in ['value', '_options_labels']:
return super(CrossSelect, self).get_state(key)
return self._composite.get_state(key)
