Small example tasks application to manage multiple windows

example_task_app.py

"""Simple self-contained tasks application

Use Window -> New Window to create new windows. Without a default layout,
File -> Exit will cause the following exception if there are multilpe
windows open:

Traceback (most recent call last):
  File "/data/home/rob/src/enthought/pyface/pyface/ui/wx/action/action_item.py", line 260, in _on_menu
    self.controller.perform(action, action_event)
  File "/data/home/rob/src/enthought/pyface/pyface/tasks/action/task_action_controller.py", line 31, in perform
    return action.perform(event)
  File "/data/home/rob/src/enthought/pyface/pyface/tasks/action/listening_action.py", line 58, in perform
    method()
  File "step2a.py", line 85, in exit
    self.window.application.exit()
  File "/data/home/rob/src/enthought/envisage/envisage/ui/tasks/tasks_application.py", line 252, in exit
    self._prepare_exit()
  File "/data/home/rob/src/enthought/envisage/envisage/ui/tasks/tasks_application.py", line 308, in _prepare_exit
    self._save_state()
  File "/data/home/rob/src/enthought/envisage/envisage/ui/tasks/tasks_application.py", line 356, in _save_state
    window_layouts = [ w.get_window_layout() for w in self.windows ]
  File "/data/home/rob/src/enthought/pyface/pyface/tasks/task_window.py", line 306, in get_window_layout
    size_state=self.size_state)

"""
# Enthought library imports.
from envisage.api import ExtensionPoint, Plugin
from envisage.ui.tasks.api import TasksApplication, TaskFactory
from pyface.api import GUI, ConfirmationDialog, FileDialog, \
    ImageResource, YES, OK, CANCEL
from pyface.tasks.api import Task, TaskWindow, TaskLayout, TaskWindowLayout, \
    PaneItem, IEditor, IEditorAreaPane, EditorAreaPane, Editor
from pyface.tasks.action.api import DockPaneToggleGroup, SMenuBar, \
    SMenu, SToolBar, TaskAction
from traits.api import on_trait_change, Property, Instance, List

from envisage.core_plugin import CorePlugin
from envisage.ui.tasks.tasks_plugin import TasksPlugin


class ExampleTask(Task):
    """ A simple task for opening a blank editor.
    """

    #### Task interface #######################################################

    id = 'example.example_task'
    name = 'Multi-Tab Editor'

    active_editor = Property(Instance(IEditor),
                             depends_on='editor_area.active_editor')

    editor_area = Instance(IEditorAreaPane)

    ###########################################################################
    # 'Task' interface.
    ###########################################################################

    def _menu_bar_default(self):
        return SMenuBar(SMenu(TaskAction(name='New', method='new',
                                         accelerator='Ctrl+N'),
                              TaskAction(name='Exit', method='exit',
                                         accelerator='Ctrl+Q'),
                              id='File', name='&File'),
                        SMenu(TaskAction(name='New Window', method='new_window',
                                         accelerator='Ctrl+W'),
                              id='Window', name='&Window'),
                        )

    def create_central_pane(self):
        """ Create the central pane: the script editor.
        """
        self.editor_area = EditorAreaPane()
        return self.editor_area

    ###########################################################################
    # 'ExampleTask' interface.
    ###########################################################################

    def new(self):
        """ Opens a new empty window
        """
        editor = Editor()
        self.editor_area.add_editor(editor)
        self.editor_area.activate_editor(editor)
        self.activated()

    def new_window(self):
        """ Opens a new empty window
        """
        print "Opening new window!!!"
        window = self.window.application.create_window()
        print "  window=%s" % str(window)
        print "  self=%s" % str(self.window)
        task = ExampleTask()
        window.add_task(task)
        window.activate_task(task)
        window.open()
        print "All windows: %s" % self.window.application.windows

    def exit(self):
        """ Opens a new empty window
        """
        print "Quitting!!!"
        self.window.application.exit()

    #### Trait property getter/setters ########################################

    def _get_active_editor(self):
        if self.editor_area is not None:
            return self.editor_area.active_editor
        return None

class ExamplePlugin(Plugin):
    """ The sample framework plugin.
    """

    # Extension point IDs.
    TASKS             = 'envisage.ui.tasks.tasks'

    #### 'IPlugin' interface ##################################################

    # The plugin's unique identifier.
    id = 'example.plugin'

    # The plugin's name (suitable for displaying to the user).
    name = 'Plugin'

    #### Contributions to extension points made by this plugin ################

    tasks = List(contributes_to=TASKS)

    ###########################################################################
    # Protected interface.
    ###########################################################################

    def _tasks_default(self):
        return [ 
            TaskFactory(id = 'example.example_task',
                        name = 'ExampleTask',
                        factory = ExampleTask),
            ]


class ExampleApplication(TasksApplication):
    """ The sample framework Tasks application.
    """

    #### 'IApplication' interface #############################################

    # The application's globally unique identifier.
    id = 'example.application'

    # The application's user-visible name.
    name = 'Application'

    ###########################################################################
    # Private interface.
    ###########################################################################

    #### Trait initializers ###################################################

    def _default_layout_default(self):
        tasks = [ factory.id for factory in self.task_factories ]
        return [ TaskWindowLayout(*tasks,
                                  size = (800, 600)) ]

def main(argv):
    """ A simple example of using Tasks.
    """
    plugins = [ CorePlugin(), TasksPlugin(), ExamplePlugin() ]
    app = ExampleApplication(plugins=plugins)
    
    app.run()


if __name__ == '__main__':
    import sys
    main(sys.argv)