Source code for pyface.fields.i_field

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""" The field interface. """


from traits.api import Any, HasTraits

from pyface.i_layout_widget import ILayoutWidget


[docs]class IField(ILayoutWidget): """ The field interface. A field is a widget that displays a value and (potentially) allows a user to interact with it. """ #: The value held by the field. value = Any()
[docs]class MField(HasTraits): """ The field mix-in. """ #: The value held by the field. value = Any() # ------------------------------------------------------------------------ # IWidget interface # ------------------------------------------------------------------------ def _add_event_listeners(self): """ Set up toolkit-specific bindings for events """ super()._add_event_listeners() self.observe(self._value_updated, "value", dispatch="ui") def _remove_event_listeners(self): """ Remove toolkit-specific bindings for events """ self.observe( self._value_updated, "value", dispatch="ui", remove=True ) super()._remove_event_listeners() # ------------------------------------------------------------------------ # Private interface # ------------------------------------------------------------------------ def _create(self): """ Creates the toolkit specific control. This method should create the control and assign it to the :py:attr:``control`` trait. """ super()._create() self.show(self.visible) self.enable(self.enabled) def _update_value(self, value): """ Handle a change to the value from user interaction This is a method suitable for calling from a toolkit event handler. """ self.value = self._get_control_value() def _get_control(self): """ If control is not passed directly, get it from the trait. """ control = self.control if control is None: raise RuntimeError("Toolkit control does not exist.") return control # Toolkit control interface --------------------------------------------- def _get_control_value(self): """ Toolkit specific method to get the control's value. """ raise NotImplementedError() def _set_control_value(self, value): """ Toolkit specific method to set the control's value. """ raise NotImplementedError() def _observe_control_value(self, remove=False): """ Toolkit specific method to change the control value observer. """ raise NotImplementedError() # Trait change handlers ------------------------------------------------- def _value_updated(self, event): value = event.new if self.control is not None: self._set_control_value(value)