Allow popup display of completions in EnumEditor

[corranwebster]

Via @chenqi0805 and @ERAnderson - the ability to have a popup showing potential completions in an EnumEditor as the user types is useful when there are potentially a large number of completions:

This can be achieved in Qt with a handler which sets the completer mode on the control; but it would be nice to have this exposed as an option in the Editor.

[corranwebster]

Code from @ERAnderson:

""" EnumEditor with auto drop down for completion - quick hack """

from pyface.qt import QtGui
from traits.api import HasTraits, Enum, List
from traitsui.api import Item, Group, View, EnumEditor, Handler


class QTEnumDropHandler(Handler):

    def init(self, info):

        for value_editor in info.ui._editors:
            if value_editor.name == 'enum_value':
                break
        else:
            ValueError("'enum_value' editor not found in search element")

        control = value_editor.control

        control.completer().setCompletionMode(
            QtGui.QCompleter.CompletionMode.PopupCompletion)

        return True


class EnumEditorDemo(HasTraits):
    """ Defines the main EnumEditor demo class. """

    # Define possible values for enum
    name_list = List(['A-495', 'A-498', 'R-1226', 'TS-17', 'TS-18',
                      'Foo', 'frombicator_a', 'whitzlegidget', 'splatzleblock',
                      'frombicator_b', 'foozalator'])

    # Define an Enum trait to view
    enum_value = Enum(values='name_list')

    def default_traits_view(self):

        enum_group = Group(
            Item('enum_value',
                 editor=EnumEditor(
                     name='name_list',
                     evaluate=True,
                 ),
                 label='Drop down with completion'),

        )

        return View(
            enum_group,
            title='EnumEditor',
            buttons=['OK'],
            resizable=True,
            handler=QTEnumDropHandler(),
        )


# Create the demo:
demo = EnumEditorDemo()


# Run the demo (if invoked from the command line):
if __name__ == '__main__':
    demo.configure_traits()