Source code for pyface.tree.node_tree_model

# (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!

""" The model for a tree control with extensible node types. """


from traits.api import Dict, Instance


from .node_manager import NodeManager
from .tree_model import TreeModel


[docs]class NodeTreeModel(TreeModel): """ The model for a tree control with extensible node types. """ # 'NodeTreeModel' interface -------------------------------------------- # The node manager looks after all node types. node_manager = Instance(NodeManager, ()) # Private interface ---------------------------------------------------- # Node monitors. _monitors = Dict() # ------------------------------------------------------------------------ # 'TreeModel' interface. # ------------------------------------------------------------------------
[docs] def has_children(self, node): """ Returns True if a node has children, otherwise False. This method is provided in case the model has an efficient way to determine whether or not a node has any children without having to actually get the children themselves. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) if node_type.allows_children(node): has_children = node_type.has_children(node) else: has_children = False return has_children
[docs] def get_children(self, node): """ Returns the children of a node. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) # Does the node allow children (ie. a folder allows children, a file # does not)? if node_type.allows_children(node): # Get the node's children. children = node_type.get_children(node) else: children = [] return children
[docs] def get_default_action(self, node): """ Returns the default action for a node. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.get_default_action(node)
[docs] def get_drag_value(self, node): """ Get the value that is dragged for a node. By default the drag value is the node itself. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.get_drag_value(node)
[docs] def can_drop(self, node, data): """ Returns True if a node allows an object to be dropped onto it. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.can_drop(node, data)
[docs] def drop(self, node, data): """ Drops an object onto a node. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) node_type.drop(node, data)
[docs] def get_image(self, node, selected, expanded): """ Returns the label image for a node. Return None (the default) if no image is required. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.get_image(node, selected, expanded)
[docs] def get_key(self, node): """ Generate a unique key for a node. """ return self.node_manager.get_key(node)
[docs] def get_selection_value(self, node): """ Get the value that is used when a node is selected. By default the selection value is the node itself. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.get_selection_value(node)
[docs] def get_text(self, node): """ Returns the label text for a node. Return None if no text is required. By default we return 'str(node)'. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.get_text(node)
[docs] def can_set_text(self, node, text): """ Returns True if the node's label can be set. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.can_set_text(node, text)
[docs] def set_text(self, node, text): """ Sets the label text for a node. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.set_text(node, text)
[docs] def is_collapsible(self, node): """ Returns True if the node is collapsible, otherwise False. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.is_collapsible(node)
[docs] def is_draggable(self, node): """ Returns True if the node is draggable, otherwise False. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.is_draggable(node)
[docs] def is_editable(self, node): """ Returns True if the node is editable, otherwise False. If the node is editable, its text can be set via the UI. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.is_editable(node)
[docs] def is_expandable(self, node): """ Returns True if the node is expandanble, otherwise False. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.is_expandable(node)
[docs] def add_listener(self, node): """ Adds a listener for changes to a node. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) # Create a monitor to listen for changes to the node. monitor = node_type.get_monitor(node) if monitor is not None: self._start_monitor(monitor) self._monitors[self.node_manager.get_key(node)] = monitor
[docs] def remove_listener(self, node): """ Removes a listener for changes to a node. """ key = self.node_manager.get_key(node) monitor = self._monitors.get(key) if monitor is not None: self._stop_monitor(monitor) del self._monitors[key] return
# ------------------------------------------------------------------------ # 'NodeTreeModel' interface. # ------------------------------------------------------------------------
[docs] def get_context_menu(self, node): """ Returns the context menu for a node. """ # Determine the node type for this node. node_type = self.node_manager.get_node_type(node) return node_type.get_context_menu(node)
# ------------------------------------------------------------------------ # 'Private' interface # ------------------------------------------------------------------------ def _start_monitor(self, monitor): """ Starts a monitor. """ monitor.observe(self._on_nodes_changed, "nodes_changed") monitor.observe(self._on_nodes_inserted, "nodes_inserted") monitor.observe(self._on_nodes_removed, "nodes_removed") monitor.observe(self._on_nodes_replaced, "nodes_replaced") monitor.observe(self._on_structure_changed, "structure_changed") monitor.start() def _stop_monitor(self, monitor): """ Stops a monitor. """ monitor.observe(self._on_nodes_changed, "nodes_changed", remove=True) monitor.observe(self._on_nodes_inserted, "nodes_inserted", remove=True) monitor.observe(self._on_nodes_removed, "nodes_removed", remove=True) monitor.observe(self._on_nodes_replaced, "nodes_replaced", remove=True) monitor.observe( self._on_structure_changed, "structure_changed", remove=True ) monitor.stop() return # Trait event handlers ------------------------------------------------- # Static ---- # fixme: Commented this out as listeners are added and removed by the tree. # This caused duplicate monitors to be created for the root node. ## def _root_changed(self, old, new): ## """ Called when the root of the model has been changed. """ ## if old is not None: ## # Remove a listener for structure/appearance changes ## self.remove_listener(old) ## if new is not None: ## # Wire up a listener for structure/appearance changes ## self.add_listener(new) ## return # Dynamic ---- def _on_nodes_changed(self, event): """ Called when nodes have changed. """ self.nodes_changed = event.new def _on_nodes_inserted(self, event): """ Called when nodes have been inserted. """ self.nodes_inserted = event.new def _on_nodes_removed(self, event): """ Called when nodes have been removed. """ self.nodes_removed = event.new def _on_nodes_replaced(self, event): """ Called when nodes have been replaced. """ self.nodes_replaced = event.new def _on_structure_changed(self, event): """ Called when the structure of a node has changed drastically. """ self.structure_changed = event.new return