===========
RadioWidget
===========

The RadioWidget renders a radio input type field e.g. <input type="radio" />

  >>> from zope.interface.verify import verifyClass
  >>> from z3c.form import interfaces
  >>> from z3c.form.browser import radio

The RadioWidget is a widget:

 >>> verifyClass(interfaces.IWidget, radio.RadioWidget)
  True

The widget can render a input field only by adapting a request:

  >>> from z3c.form.testing import TestRequest
  >>> request = TestRequest()
  >>> widget = radio.RadioWidget(request)

Set a name and id for the widget:

  >>> widget.id = 'widget-id'
  >>> widget.name = 'widget.name'

Such a field provides IWidget:

 >>> interfaces.IWidget.providedBy(widget)
  True

We also need to register the template for at least the widget and request:

  >>> import os.path
  >>> import zope.interface
  >>> from zope.publisher.interfaces.browser import IDefaultBrowserLayer
  >>> from zope.pagetemplate.interfaces import IPageTemplate
  >>> import z3c.form.browser
  >>> import z3c.form.widget
  >>> template = os.path.join(os.path.dirname(z3c.form.browser.__file__),
  ...     'radio_input.pt')
  >>> factory = z3c.form.widget.WidgetTemplateFactory(template)
  >>> zope.component.provideAdapter(factory,
  ...     (zope.interface.Interface, IDefaultBrowserLayer, None, None, None),
  ...     IPageTemplate, name='input')

If we render the widget we only get the empty marker:

  >>> print widget.render()
  <input name="widget.name-empty-marker" type="hidden" value="1" />

Let's provide some values for this widget. We can do this by defining a source
providing ITerms. This source uses descriminators wich will fit for our setup.

  >>> import zope.schema.interfaces
  >>> import z3c.form.term
  >>> from zc.sourcefactory.basic import BasicSourceFactory
  >>> class YesNoSourceFactory(BasicSourceFactory):
  ...     def getValues(self):
  ...         return ['yes', 'no']
  >>> class MyTerms(z3c.form.term.ChoiceTermsSource):
  ...     def __init__(self, context, request, form, field, widget):
  ...         self.terms = YesNoSourceFactory()
  >>> zope.component.provideAdapter(z3c.form.term.BoolTerms,
  ...     adapts=(zope.interface.Interface,
  ...             interfaces.IFormLayer, zope.interface.Interface,
  ...             zope.interface.Interface, interfaces.IRadioWidget))

Now let's try if we get widget values:

  >>> widget.update()
  >>> print widget.render()
  <span class="option">
    <label for="widget-id-0">
      <input type="radio" id="widget-id-0" name="widget.name:list"
             class="radio-widget" value="true" />
      <span class="label">yes</span>
    </label>
  </span><span class="option">
    <label for="widget-id-1">
      <input type="radio" id="widget-id-1" name="widget.name:list"
             class="radio-widget" value="false" />
      <span class="label">no</span>
    </label>
  </span>
  <input name="widget.name-empty-marker" type="hidden" value="1" />

If we set the value for the widget to ``yes``, we can se that the radio field
get rendered with a checked flag:

  >>> widget.value = 'true'
  >>> widget.update()
  >>> print widget.render()
  <span class="option">
    <label for="widget-id-0">
      <input type="radio" id="widget-id-0" name="widget.name:list"
             class="radio-widget" value="true" checked="checked" />
      <span class="label">yes</span>
    </label>
  </span><span class="option">
    <label for="widget-id-1">
      <input type="radio" id="widget-id-1" name="widget.name:list"
             class="radio-widget" value="false" />
      <span class="label">no</span>
    </label>
  </span>
  <input name="widget.name-empty-marker" type="hidden" value="1" />
