widget_button.py
92 lines
| 3.2 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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r14540 | from .widget import DOMWidget | ||
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r14270 | from IPython.utils.traitlets import Unicode, Bool, Int | ||
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r14283 | #----------------------------------------------------------------------------- | ||
# Classes | ||||
#----------------------------------------------------------------------------- | ||||
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r14540 | class ButtonWidget(DOMWidget): | ||
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r14270 | target_name = Unicode('ButtonWidgetModel') | ||
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r14590 | view_name = Unicode('ButtonView', sync=True) | ||
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r14283 | |||
# Keys | ||||
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r14588 | description = Unicode('', help="Description of the button (label).", sync=True) | ||
disabled = Bool(False, help="Enable or disable user changes.", sync=True) | ||||
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r14270 | |||
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r14315 | |||
def __init__(self, **kwargs): | ||||
super(ButtonWidget, self).__init__(**kwargs) | ||||
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r14400 | |||
self._click_handlers = [] | ||||
self.on_msg(self._handle_button_msg) | ||||
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r14270 | |||
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r14272 | |||
def on_click(self, callback, remove=False): | ||||
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r14320 | """Register a callback to execute when the button is clicked. The | ||
callback can either accept no parameters or one sender parameter: | ||||
- callback() | ||||
- callback(sender) | ||||
If the callback has a sender parameter, the ButtonWidget instance that | ||||
called the callback will be passed into the method as the sender. | ||||
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r14283 | |||
Parameters | ||||
---------- | ||||
remove : bool (optional) | ||||
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r14320 | Set to true to remove the callback from the list of callbacks.""" | ||
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r14270 | if remove: | ||
self._click_handlers.remove(callback) | ||||
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r14331 | elif not callback in self._click_handlers: | ||
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r14270 | self._click_handlers.append(callback) | ||
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r14272 | |||
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r14400 | def _handle_button_msg(self, content): | ||
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r14486 | """Handle a msg from the front-end | ||
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r14400 | |||
Parameters | ||||
---------- | ||||
content: dict | ||||
Content of the msg.""" | ||||
if 'event' in content and content['event'] == 'click': | ||||
self._handle_click() | ||||
def _handle_click(self): | ||||
"""Handles when the button has been clicked. Fires on_click | ||||
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r14283 | callbacks when appropriate.""" | ||
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r14400 | |||
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.') | ||||