widget_button.py
72 lines
| 2.6 KiB
| text/x-python
|
PythonLexer
|
r14283 | """ButtonWidget class. | ||
Represents a button in the frontend using a widget. Allows user to listen for | ||||
click events on the button and trigger backend code when the clicks are fired. | ||||
""" | ||||
#----------------------------------------------------------------------------- | ||||
# Copyright (c) 2013, the IPython Development Team. | ||||
# | ||||
# Distributed under the terms of the Modified BSD License. | ||||
# | ||||
# The full license is in the file COPYING.txt, distributed with this software. | ||||
#----------------------------------------------------------------------------- | ||||
#----------------------------------------------------------------------------- | ||||
# Imports | ||||
#----------------------------------------------------------------------------- | ||||
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r14272 | import inspect | ||
import types | ||||
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r14274 | from widget import Widget | ||
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r14270 | from IPython.utils.traitlets import Unicode, Bool, Int | ||
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r14283 | #----------------------------------------------------------------------------- | ||
# Classes | ||||
#----------------------------------------------------------------------------- | ||||
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r14270 | class ButtonWidget(Widget): | ||
target_name = Unicode('ButtonWidgetModel') | ||||
default_view_name = Unicode('ButtonView') | ||||
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r14283 | |||
# Keys | ||||
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r14270 | _keys = ['clicks', 'description', 'disabled'] | ||
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r14283 | clicks = Int(0, help="Number of times the button has been clicked.") | ||
description = Unicode('', help="Description of the button (label).") | ||||
disabled = Bool(False, help="Enable or disable user changes.") | ||||
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r14270 | |||
_click_handlers = [] | ||||
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r14272 | |||
def on_click(self, callback, remove=False): | ||||
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r14283 | """Register a callback to execute when the button is clicked. | ||
Parameters | ||||
---------- | ||||
remove : bool (optional) | ||||
Set to tru to remove the callback from the list of callbacks.""" | ||||
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r14270 | if remove: | ||
self._click_handlers.remove(callback) | ||||
else: | ||||
self._click_handlers.append(callback) | ||||
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r14272 | |||
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r14270 | def _clicks_changed(self, name, old, new): | ||
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r14283 | """Handles when the clicks property has been changed. Fires on_click | ||
callbacks when appropriate.""" | ||||
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r14270 | if new > old: | ||
for handler in self._click_handlers: | ||||
if callable(handler): | ||||
argspec = inspect.getargspec(handler) | ||||
nargs = len(argspec[0]) | ||||
# Bound methods have an additional 'self' argument | ||||
if isinstance(handler, types.MethodType): | ||||
nargs -= 1 | ||||
# Call the callback | ||||
if nargs == 0: | ||||
handler() | ||||
elif nargs == 1: | ||||
handler(self) | ||||
else: | ||||
raise TypeError('ButtonWidget click callback must ' \ | ||||
'accept 0 or 1 arguments.') | ||||