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Remove init_widget_js, use require.js for everything...
Remove init_widget_js, use require.js for everything Updated examples Fixed bug with message throttling

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Part 2 - Events.ipynb
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/ examples / widgets / Part 2 - Events.ipynb
Jonathan Frederic
Uploaded widget tutorial (example) notebooks.
r14323 {
"metadata": {
Jonathan Frederic
Remove init_widget_js, use require.js for everything...
r14342 "cell_tags": [
[
"<None>",
null
]
],
Jonathan Frederic
Uploaded widget tutorial (example) notebooks.
r14323 "name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "code",
"collapsed": false,
"input": [
"from IPython.html import widgets # Widget definitions\n",
Jonathan Frederic
Remove init_widget_js, use require.js for everything...
r14342 "from IPython.display import display # Used to display widgets in the notebook"
Jonathan Frederic
Uploaded widget tutorial (example) notebooks.
r14323 ],
"language": "python",
"metadata": {},
Jonathan Frederic
Remove init_widget_js, use require.js for everything...
r14342 "outputs": [],
Jonathan Frederic
Uploaded widget tutorial (example) notebooks.
r14323 "prompt_number": 1
},
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Traitlet Events"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"The widget properties are IPython traitlets. Traitlets are eventful. To handle property value changes, the `on_trait_change` method of the widget can be used to register an event handling callback. The doc string for `on_trait_change` can be seen below. Both the `name` and `remove` properties are optional."
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print(widgets.Widget.on_trait_change.__doc__)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Setup a handler to be called when a trait changes.\n",
"\n",
" This is used to setup dynamic notifications of trait changes.\n",
"\n",
" Static handlers can be created by creating methods on a HasTraits\n",
" subclass with the naming convention '_[traitname]_changed'. Thus,\n",
" to create static handler for the trait 'a', create the method\n",
" _a_changed(self, name, old, new) (fewer arguments can be used, see\n",
" below).\n",
"\n",
" Parameters\n",
" ----------\n",
" handler : callable\n",
" A callable that is called when a trait changes. Its\n",
" signature can be handler(), handler(name), handler(name, new)\n",
" or handler(name, old, new).\n",
" name : list, str, None\n",
" If None, the handler will apply to all traits. If a list\n",
" of str, handler will apply to all names in the list. If a\n",
" str, the handler will apply just to that name.\n",
" remove : bool\n",
" If False (the default), then install the handler. If True\n",
" then unintall it.\n",
" \n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Mentioned in the doc string, the callback registered can have 4 possible signatures:\n",
"\n",
"- callback()\n",
"- callback(trait_name)\n",
"- callback(trait_name, new_value)\n",
"- callback(trait_name, old_value, new_value)\n",
"\n",
"An example of how to output an IntRangeWiget's value as it is changed can be seen below."
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"intrange = widgets.IntRangeWidget()\n",
"display(intrange)\n",
"\n",
"def on_value_change(name, value):\n",
" print value\n",
"\n",
"intrange.on_trait_change(on_value_change, 'value')"
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Specialized Events"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Button On Click Event"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"The `ButtonWidget` is a special widget, like the `ContainerWidget` and `MulticontainerWidget`, that isn't used to represent a data type. Instead the button widget is used to handle mouse clicks. The `on_click` method of the `ButtonWidget` can be used to register a click even handler. The doc string of the `on_click` can be seen below."
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"print(widgets.ButtonWidget.on_click.__doc__)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Register a callback to execute when the button is clicked. The\n",
" callback can either accept no parameters or one sender parameter:\n",
" - callback()\n",
" - callback(sender)\n",
" If the callback has a sender parameter, the ButtonWidget instance that\n",
" called the callback will be passed into the method as the sender.\n",
"\n",
" Parameters\n",
" ----------\n",
" remove : bool (optional)\n",
" Set to true to remove the callback from the list of callbacks.\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Button clicks are tracked by the `clicks` property of the button widget. By using the `on_click` method and the `clicks` property, a button that outputs how many times it has been clicked is shown below."
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"button = widgets.ButtonWidget(description=\"Click Me!\")\n",
"display(button)\n",
"\n",
"def on_button_clicked(sender):\n",
" print(\"Button clicked %d times.\" % sender.clicks)\n",
"\n",
"button.on_click(on_button_clicked)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Button clicked 1 times.\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Button clicked 2 times.\n"
]
},
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Button clicked 3 times.\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Event handlers can also be used to create widgets. In the example below, clicking a button spawns another button with a description equal to how many times the parent button had been clicked at the time."
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"def show_button(sender=None):\n",
" button = widgets.ButtonWidget()\n",
" button.description = \"%d\" % (sender.clicks if sender is not None else 0)\n",
" display(button)\n",
" button.on_click(show_button)\n",
"show_button()\n",
" "
],
"language": "python",
"metadata": {},
"outputs": [],
"prompt_number": 6
}
],
"metadata": {}
}
]
}