class MuntjacComboBox(MuntjacControl, AbstractTkComboBox):
""" A Muntjac implementation of ComboBox.
Use a combo box to select a single item from a collection of items.
"""
#--------------------------------------------------------------------------
# Setup methods
#--------------------------------------------------------------------------
def create(self, parent):
""" Creates a QComboBox.
"""
self.widget = ComboBox()
self.widget.setImmediate(True)
parent.addComponent(self.widget)
def initialize(self):
""" Intializes the widget with the attributes of this instance.
"""
super(MuntjacComboBox, self).initialize()
shell = self.shell_obj
self.set_items(shell.labels)
self.set_selection(shell.index)
def bind(self):
""" Connects the event handlers for the combo box.
"""
super(MuntjacComboBox, self).bind()
self.widget.currentIndexChanged.connect(self.on_selected)
#--------------------------------------------------------------------------
# Implementation
#--------------------------------------------------------------------------
def shell_index_changed(self, index):
""" The change handler for the 'index' attribute on the shell
object.
"""
self.set_selection(index)
def shell_labels_changed(self, labels):
""" The change handler for the 'labels' attribute on the shell
object.
"""
self.set_items(labels)
def on_selected(self):
""" The event handler for a combo box selection event.
"""
if not guard.guarded(self, 'updating'):
shell = self.shell_obj
curr_index = self._selected_index()
shell.index = curr_index
# Only fire the selected event if we have a valid selection
if curr_index != -1:
shell.selected = shell.value
def set_items(self, str_items):
""" Sets the items in the combo box.
"""
# We need to avoid a feedback loop when updating the items in
# the combo box. Qt will emit index changed signals when the
# items are updated. But, the shell object has already computed
# the proper index for the new items, so we use that to update
# the index of the control after updating the items. The flag
# is read by the on_selected handler to ignore updates during
# this process.
with guard(self, 'updating'):
widget = self.widget
widget.removeAllItems()
for item in str_items:
widget.addItem(item)
ids = widget.getItemIds()
widget.select(ids[self.shell_obj.index])
def set_selection(self, index):
""" Sets the value in the combo box, or resets the combo box
if the value is not in the list of items.
"""
# We need to avoid a feedback loop when updating the selection
# in the combo box. Qt will emit index changed signals when the
# selectino is updated. But, the shell object has already computed
# the proper index for the new selection so we don't need to feed
# back while doing this.
with guard(self, 'updating'):
ids = self.widget.getItemIds()
self.widget.select(ids[index])
#--------------------------------------------------------------------------
# Helper Methods
#--------------------------------------------------------------------------
def _selected_index(self):
widget = self.widget
ids = widget.getItemIds()
val = widget.getValue()
if val in ids:
curr_index = ids.index(val)
else:
curr_index = -1
return curr_index
