#------------------------------------------------------------------------------ # # Copyright (c) 2005, Enthought, Inc. # All rights reserved. # # This software is provided without warranty under the terms of the BSD # license included in enthought/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! # # Author: David C. Morrill # Date: 10/07/2004 # #------------------------------------------------------------------------------ """ Defines the Handler class used to manage and control the editing process in a Traits-based user interface. """ #------------------------------------------------------------------------------- # Imports: #------------------------------------------------------------------------------- from __future__ import absolute_import from .toolkit import toolkit from .help import on_help_call from .view_element import ViewElement from .helper import user_name_for from .ui_info import UIInfo from traits.api import HasPrivateTraits, HasTraits, Instance #------------------------------------------------------------------------------- # Closes a DockControl (if allowed by the associated traits UI Handler): #------------------------------------------------------------------------------- def close_dock_control ( dock_control ): """ Closes a DockControl (if allowed by the associated Traits UI Handler). """ # Retrieve the traits UI object set when we created the DockControl: ui = dock_control.data # Ask the traits UI handler if it is OK to close the window: if not ui.handler.close( ui.info, True ): # If not, tell the DockWindow not to close it: return False # Otherwise, clean up and close the traits UI: ui.dispose() # And tell the DockWindow to remove the DockControl: return True #------------------------------------------------------------------------------- # 'Handler' class: #------------------------------------------------------------------------------- class Handler ( HasPrivateTraits ): """ Provides access to and control over the run-time workings of a Traits-based user interface. """ #--------------------------------------------------------------------------- # Informs the handler what the UIInfo object for a View will be: #--------------------------------------------------------------------------- def init_info ( self, info ): """ Informs the handler what the UIInfo object for a View will be. This method is called before the UI for the View has been constructed. It is provided so that the handler can save the reference to the UIInfo object in case it exposes viewable traits whose values are properties that depend upon items in the context being edited. """ pass #--------------------------------------------------------------------------- # Initializes the controls of a user interface: #--------------------------------------------------------------------------- def init ( self, info ): """ Initializes the controls of a user interface. Parameters ---------- info : UIInfo object The UIInfo object associated with the view Returns ------- A Boolean, indicating whether the user interface was successfully initialized. A True value indicates that the UI can be displayed; a False value indicates that the display operation should be cancelled. The default implementation returns True without taking any other action. Description ----------- This method is called after all user interface elements have been created, but before the user interface is displayed. Override this method to customize the user interface before it is displayed. """ return True #--------------------------------------------------------------------------- # Positions a dialog-based user interface on the display: #--------------------------------------------------------------------------- def position ( self, info ): """ Positions a dialog-based user interface on the display. Parameters ---------- info : UIInfo object The UIInfo object associated with the window Returns ------- Nothing. Description ----------- This method is called after the user interface is initialized (by calling init()), but before the user interface is displayed. Override this method to position the window on the display device. The default implementation calls the position() method of the current toolkit. Usually, you do not need to override this method, because you can control the window's placement using the **x** and **y** attributes of the View object. """ toolkit().position( info.ui ) #--------------------------------------------------------------------------- # Handles a request to close a dialog-based user interface by the user: #--------------------------------------------------------------------------- def close ( self, info, is_ok ): """ Handles the user attempting to close a dialog-based user interface. Parameters ---------- info : UIInfo object The UIInfo object associated with the view is_ok : Boolean Indicates whether the user confirmed the changes (such as by clicking **OK**.) Returns ------- A Boolean, indicating whether the window should be allowed to close. Description ----------- This method is called when the user attempts to close a window, by clicking an **OK** or **Cancel** button, or clicking a Close control on the window). It is called before the window is actually destroyed. Override this method to perform any checks before closing a window. While Traits UI handles "OK" and "Cancel" events automatically, you can use the value of the *is_ok* parameter to implement additional behavior. """ return True #--------------------------------------------------------------------------- # Handles a dialog-based user interface being closed by the user: #--------------------------------------------------------------------------- def closed ( self, info, is_ok ): """ Handles a dialog-based user interface being closed by the user. Parameters ---------- info : UIInfo object The UIInfo object associated with the view is_ok : Boolean Indicates whether the user confirmed the changes (such as by clicking **OK**.) Description ----------- This method is called *after* the window is destroyed. Override this method to perform any clean-up tasks needed by the application. """ return #--------------------------------------------------------------------------- # Handles the 'Revert' button being clicked: #--------------------------------------------------------------------------- def revert ( self, info ): """ Handles the **Revert** button being clicked. """ return #--------------------------------------------------------------------------- # Handles the 'Apply' button being clicked: #--------------------------------------------------------------------------- def apply ( self, info ): """ Handles the **Apply** button being clicked. """ return #--------------------------------------------------------------------------- # Shows the help associated with the view: #--------------------------------------------------------------------------- def show_help ( self, info, control = None ): """ Shows the help associated with the view. Parameters ---------- info : UIInfo object The UIInfo object associated with the view control : UI control The control that invokes the help dialog box Description ----------- This method is called when the user clicks a **Help** button in a Traits user interface. The method calls the global help handler, which might be the default help handler, or might be a custom help handler. See **traitsui.help** for details about the setting the global help handler. """ if control is None: control = info.ui.control on_help_call()( info, control ) #--------------------------------------------------------------------------- # Handles setting a specified object trait's value: #--------------------------------------------------------------------------- def setattr ( self, info, object, name, value ): """ Handles the user setting a specified object trait's value. Parameters ---------- object : object The object whose attribute is being set name : string The name of the attribute being set value The value to which the attribute is being set Description ----------- This method is called when an editor attempts to set a new value for a specified object trait attribute. Use this method to control what happens when a trait editor tries to set an attribute value. For example, you can use this method to record a history of changes, in order to implement an "undo" mechanism. No result is returned. The default implementation simply calls the built-in setattr() function. If you override this method, make sure that it actually sets the attribute, either by calling the parent method or by setting the attribute directly """ setattr( object, name, value ) #--------------------------------------------------------------------------- # Gets a specified View object: #--------------------------------------------------------------------------- def trait_view_for ( self, info, view, object, object_name, trait_name ): """ Gets a specified View object. """ # If a view element was passed instead of a name or None, return it: if isinstance( view, ViewElement ): return view # Generate a series of possible view or method names of the form: # - 'view' # trait_view_for_'view'( object ) # - 'class_view' # trait_view_for_'class_view'( object ) # - 'object_name_view' # trait_view_for_'object_name_view'( object ) # - 'object_name_class_view' # trait_view_for_'object_name_class_view'( object ) # where 'class' is the class name of 'object', 'object' is the object # name, and 'name' is the trait name. It returns the first view # or method result which is defined on the handler: klass = object.__class__.__name__ cname = '%s_%s' % ( object_name, trait_name ) aview = '' if view: aview = '_' + view names = [ '%s_%s%s' % ( cname, klass, aview ), '%s%s' % ( cname, aview ), '%s%s' % ( klass, aview ) ] if view: names.append( view ) for name in names: result = self.trait_view( name ) if result is not None: return result method = getattr( self, 'trait_view_for_%s' % name, None ) if callable( method ): result = method( info, object ) if result is not None: return result # If nothing is defined on the handler, return either the requested # view on the object itself, or the object's default view: return object.trait_view( view ) or object.trait_view() #-- 'DockWindowHandler' interface implementation ------------------------------- #--------------------------------------------------------------------------- # Returns whether or not a specified object can be inserted into the view: #--------------------------------------------------------------------------- def can_drop ( self, info, object ): """ Can the specified object be inserted into the view? """ from pyface.dock.api import DockControl if isinstance( object, DockControl ): return self.can_import( info, object.export ) drop_class = info.ui.view.drop_class return ((drop_class is not None) and isinstance( object, drop_class )) #--------------------------------------------------------------------------- # Returns whether or not a specified external view category can be # imported: #--------------------------------------------------------------------------- def can_import ( self, info, category ): return (category in info.ui.view.imports) #--------------------------------------------------------------------------- # Returns the DockControl object for a specified object: #--------------------------------------------------------------------------- def dock_control_for ( self, info, parent, object ): """ Returns the DockControl object for a specified object. """ from pyface.dock.api import IDockable, DockControl from .dockable_view_element import DockableViewElement try: name = object.name except: try: name = object.label except: name = '' if len( name ) == 0: name = user_name_for( object.__class__.__name__ ) image = None export = '' if isinstance( object, DockControl ): dock_control = object image = dock_control.image export = dock_control.export dockable = dock_control.dockable close = dockable.dockable_should_close() if close: dock_control.close( force = True ) control = dockable.dockable_get_control( parent ) # If DockControl was closed, then reset it to point to the new # control: if close: dock_control.set( control = control, style = parent.owner.style ) dockable.dockable_init_dockcontrol( dock_control ) return dock_control elif isinstance( object, IDockable ): dockable = object control = dockable.dockable_get_control( parent ) else: ui = object.get_dockable_ui( parent ) dockable = DockableViewElement( ui = ui ) export = ui.view.export control = ui.control dc = DockControl( control = control, name = name, export = export, style = parent.owner.style, image = image, closeable = True ) dockable.dockable_init_dockcontrol( dc ) return dc #--------------------------------------------------------------------------- # Creates a new view of a specified control: #--------------------------------------------------------------------------- def open_view_for ( self, control, use_mouse = True ): """ Creates a new view of a specified control. """ from pyface.dock.api import DockWindowShell DockWindowShell( control, use_mouse = use_mouse ) #--------------------------------------------------------------------------- # Handles a DockWindow becoming empty: #--------------------------------------------------------------------------- def dock_window_empty ( self, dock_window ): """ Handles a DockWindow becoming empty. """ if dock_window.auto_close: dock_window.control.GetParent.Destroy() #-- HasTraits overrides: ------------------------------------------------------- #--------------------------------------------------------------------------- # Edits the object's traits: (Overrides HasTraits) #--------------------------------------------------------------------------- def edit_traits ( self, view = None, parent = None, kind = None, context = None, handler = None, id = '', scrollable = None, **args ): """ Edits the object's traits. """ if context is None: context = self if handler is None: handler = self return self.trait_view( view ).ui( context, parent, kind, self.trait_view_elements(), handler, id, scrollable, args ) #--------------------------------------------------------------------------- # Configure the object's traits (Overrides HasTraits): #--------------------------------------------------------------------------- def configure_traits ( self, filename = None, view = None, kind = None, edit = True, context = None, handler = None, id = '', scrollable = None, **args ): """ Configures the object's traits. """ super( HasPrivateTraits, self ).configure_traits( filename, view, kind, edit, context, handler or self, id, scrollable, **args ) #-- Private Methods: ----------------------------------------------------------- #--------------------------------------------------------------------------- # Handles an 'Undo' change request: #--------------------------------------------------------------------------- def _on_undo ( self, info ): """ Handles an "Undo" change request. """ if info.ui.history is not None: info.ui.history.undo() #--------------------------------------------------------------------------- # Handles a 'Redo' change request: #--------------------------------------------------------------------------- def _on_redo ( self, info ): """ Handles a "Redo" change request. """ if info.ui.history is not None: info.ui.history.redo() #--------------------------------------------------------------------------- # Handles a 'Revert' all changes request: #--------------------------------------------------------------------------- def _on_revert ( self, info ): """ Handles a "Revert all changes" request. """ if info.ui.history is not None: info.ui.history.revert() self.revert( info ) #--------------------------------------------------------------------------- # Handles a 'Close' request: #--------------------------------------------------------------------------- def _on_close ( self, info ): """ Handles a "Close" request. """ if (info.ui.owner is not None) and self.close( info, True ): info.ui.owner.close() #------------------------------------------------------------------------------- # Default handler: #------------------------------------------------------------------------------- _default_handler = Handler() def default_handler ( handler = None ): """ Returns the global default handler. If *handler* is an instance of Handler, this function sets it as the global default handler. """ global _default_handler if isinstance( handler, Handler ): _default_handler = handler return _default_handler #------------------------------------------------------------------------------- # 'Controller' class: #------------------------------------------------------------------------------- class Controller ( Handler ): """ Defines a handler class which provides a view and controller for a specified model. This class is used when implementing a standard MVC-based design. The **model** trait contains most, if not all, of the data being viewed, and can be referenced in a Controller instance's View definition using unadorned trait names. (e.g., ``Item('name')``). """ #-- Trait Definitions ------------------------------------------------------ # The model this handler defines a view and controller for model = Instance( HasTraits ) # The Info object associated with the controller info = Instance( UIInfo ) #-- HasTraits Method Overrides --------------------------------------------- def __init__ ( self, model = None, **metadata ): """ Initializes the object and sets the model (if supplied). """ super( Controller, self ).__init__( **metadata ) self.model = model def trait_context ( self ): """ Returns the default context to use for editing or configuring traits. """ return { 'object': self.model, 'controller': self, 'handler': self } #-- Handler Method Overrides ----------------------------------------------- #--------------------------------------------------------------------------- # Informs the handler what the UIInfo object for a View will be: #--------------------------------------------------------------------------- def init_info ( self, info ): """ Informs the handler what the UIInfo object for a View will be. """ self.info = info #------------------------------------------------------------------------------- # 'ModelView' class: #------------------------------------------------------------------------------- class ModelView ( Controller ): """ Defines a handler class which provides a view and controller for a specified model. This class is useful when creating a variant of the standard MVC-based design. A subclass of ModelView reformulates a number of traits on its **model** object as properties on the ModelView subclass itself, usually in order to convert them into a more user-friendly format. In this design, the ModelView subclass supplies not only the view and the controller, but also, in effect, the model (as a set of properties wrapped around the original model). Because of this, the ModelView context dictionary specifies the ModelView instance itself as the special *object* value, and assigns the original model object as the *model* value. Thus, the traits of the ModelView object can be referenced in its View definition using unadorned trait names. """ #-- HasTraits Method Overrides --------------------------------------------- def trait_context ( self ): """ Returns the default context to use for editing or configuring traits. """ return { 'object': self, 'handler': self, 'model': self.model } #------------------------------------------------------------------------------- # 'ViewHandler' class: #------------------------------------------------------------------------------- class ViewHandler ( Handler ): pass