Source code for pyface.viewer.tree_item

# (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!

""" A generic base-class for items in a tree data structure.

An example::

    root = TreeItem(data='Root')

    fruit = TreeItem(data='Fruit')
    fruit.append(TreeItem(data='Apple', allows_children=False))
    fruit.append(TreeItem(data='Orange', allows_children=False))
    fruit.append(TreeItem(data='Pear', allows_children=False))
    root.append(fruit)

    veg = TreeItem(data='Veg')
    veg.append(TreeItem(data='Carrot', allows_children=False))
    veg.append(TreeItem(data='Cauliflower', allows_children=False))
    veg.append(TreeItem(data='Sprout', allows_children=False))
    root.append(veg)

"""


from traits.api import Any, Bool, HasTraits, Instance, List, Property


[docs]class TreeItem(HasTraits): """ A generic base-class for items in a tree data structure. """ # 'TreeItem' interface ------------------------------------------------- # Does this item allow children? allows_children = Bool(True) # The item's children. children = List(Instance("TreeItem")) # Arbitrary data associated with the item. data = Any() # Does the item have any children? has_children = Property(Bool) # The item's parent. parent = Instance("TreeItem") # ------------------------------------------------------------------------ # 'object' interface. # ------------------------------------------------------------------------ def __str__(self): """ Returns the informal string representation of the object. """ if self.data is None: s = "" else: s = str(self.data) return s # ------------------------------------------------------------------------ # 'TreeItem' interface. # ------------------------------------------------------------------------ # Properties ----------------------------------------------------------- # has_children def _get_has_children(self): """ True iff the item has children. """ return len(self.children) != 0 # Methods -------------------------------------------------------------#
[docs] def append(self, child): """ Appends a child to this item. This removes the child from its current parent (if it has one). """ return self.insert(len(self.children), child)
[docs] def insert(self, index, child): """ Inserts a child into this item at the specified index. This removes the child from its current parent (if it has one). """ if child.parent is not None: child.parent.remove(child) child.parent = self self.children.insert(index, child) return child
[docs] def remove(self, child): """ Removes a child from this item. """ child.parent = None self.children.remove(child) return child
[docs] def insert_before(self, before, child): """ Inserts a child into this item before the specified item. This removes the child from its current parent (if it has one). """ index = self.children.index(before) self.insert(index, child) return (index, child)
[docs] def insert_after(self, after, child): """ Inserts a child into this item after the specified item. This removes the child from its current parent (if it has one). """ index = self.children.index(after) self.insert(index + 1, child) return (index, child)