from django.forms.utils import flatatt from django.forms.widgets import Widget from django.utils.safestring import mark_safe class TriStateCheckbox(Widget): def __init__(self, attrs=None, choices=()): super().__init__(attrs) # choices can be any iterable, but we may need to render this widget # multiple times. Thus, collapse it into a list so it can be consumed # more than once. self.choices = list(choices) def render(self, name, value, attrs=None, choices=()): if value is None: value = "none" attrs["value"] = value final_attrs = self.build_attrs(self.attrs, attrs) output = ['<span class="tristate"%s></span>' % flatatt(final_attrs)] return mark_safe("\n".join(output))