Question

What is the “djangoy” way to approach this problem:

In my form class, I have a forms.ChoiceField whose widget is a forms.RadioSelect widget, one of whose choices needs to be presented with an inline text input (which is also a field in the form). I’m using custom validation to ignore the text field when its radio choice is not selected. When rendered, I want it to appear like below:

<ul>
<li><label for="id_rad_0"><input type="radio" id="id_rad_0" value="none" name="rad" /> No Textbox</label></li>
<li><label for="id_rad_1"><input type="radio" id="id_rad_1" value="one" name="rad" /> One Textbox: <input type="text" name="bar" id="id_bar" /></label></li>
</ul>

However, I can’t simply produce this in my template, because the radio choices are not exposed. I can’t see a way to do this without tightly coupling my form to my template, or alternately, putting all of the presentation logic in the form class. What is the right way to solve this problem?

edit

I realize that the above might just be an obscure problem, but I’m not sure exactly what other information I can provide in order to inspire someone to help me with this. I’m a much better backend programmer than web designer, and I’m on this project alone, so maybe it’s a lack of education – is what I described simply poor design? Should I just be designing this a different way? I’m really open to any suggestion here that will help me move past this.

edit 2

Per request, the current code, shortened to save sanity, names changed to protect the innocent:

# forms.py
from myapp.models import RatherComplicatedModel
from django import forms

class RatherComplicatedForm(forms.ModelForm):
    #various and sundry code...
    RADIO_CHOICES = (
        ('none', "No Textbox"),
        ('one', "One Textbox: "),
    )
    # although I've abbreviated the model, 'rad' does not appear in the model;
    # it merely provides input to the un-provided clean function
    rad = forms.ChoiceField(widget=forms.RadioSelect(),choices=RADIO_CHOICES)

    class Meta:
        model = RatherComplicatedModel

–

# models.py
from django.db import models

class RatherComplicatedModel(models.Model):
    #some other stuff...
    bar = models.IntegerField(blank=True,null=True)

Answer 1

Anton’s answer worked, and was a decent answer for a while there – but unfortunately it became unmaintainable. So, taking a cue from a diff attached to django ticket #9230, I just monkey patched django.forms.forms.BoundField

from django import forms

def MonkeyPatchDjangoFormsBoundField():
    def prepare_widget_render(self, widget=None, attrs=None, only_initial=False):
        """
        Prepare the data needed for the widget rendering.
        """
        if not widget:
            widget = self.field.widget

        attrs = attrs or {}
        auto_id = self.auto_id
        if auto_id and 'id' not in attrs and 'id' not in widget.attrs:
            if not only_initial:
                attrs['id'] = auto_id
            else:
                attrs['id'] = self.html_initial_id

        if not only_initial:
            name = self.html_name
        else:
            name = self.html_initial_name

        return widget, name, attrs

    def as_widget(self, widget=None, attrs=None, only_initial=False):
        """
        Renders the field by rendering the passed widget, adding any HTML
        attributes passed as attrs.  If no widget is specified, then the
        field's default widget will be used.
        """
        widget, name, attrs = self.prepare_widget_render(widget, attrs, only_initial)
        return widget.render(name, self.value(), attrs=attrs)

    def __iter__(self):
        """
        Check if current widget has a renderer and iterate renderer.
        """
        widget, name, attrs = self.prepare_widget_render()
        if not hasattr(widget, 'get_renderer'):
            raise Exception, "Can not iterate over widget '%s'" % widget.__class__.__name__
        renderer = widget.get_renderer(name, self.value(), attrs=attrs)
        for entry in renderer:
            yield entry

    def __getitem__(self,idx):
        """
        Tries to use current widget's renderer, and then check attribute.
        """
        widget, name, attrs = self.prepare_widget_render()
        try:
            renderer = widget.get_renderer(name, self.value(), attrs=attrs)
            return renderer[idx]
        except Exception:
            return getattr(self,idx)

    forms.forms.BoundField.prepare_widget_render = prepare_widget_render
    forms.forms.BoundField.as_widget = as_widget
    forms.forms.BoundField.__iter__ = __iter__
    forms.forms.BoundField.__getitem__ = __getitem__

This allowed me to be able to access the radio inputs directly, by using {{ form.field.0.tag }}, or through iteration – {% for radio in form.field %} {{ radio.tag }} {% endfor %}. Much easier to take care of!