Source code for quantityfield.widgets
from django.forms.widgets import MultiWidget, NumberInput, Select
import pint
from .units import ureg
[docs]class QuantityWidget(MultiWidget):
def __init__(self, *, attrs=None, base_units=None, allowed_types=None):
self.ureg = ureg
choices = self.get_choices(allowed_types)
self.base_units = base_units
attrs = attrs or {}
attrs.setdefault("step", "any")
widgets = (NumberInput(attrs=attrs), Select(attrs=attrs, choices=choices))
super(QuantityWidget, self).__init__(widgets, attrs)
[docs] def get_choices(self, allowed_types=None):
allowed_types = allowed_types or dir(self.ureg)
return [(x, x) for x in allowed_types]
[docs] def decompress(self, value):
"""This function is called during rendering
It is responsible to split values for the two widgets
"""
if value:
if isinstance(value, pint.Quantity):
return [value.magnitude, value.units]
else:
# We assume that the given value is a proper number,
# ready to be rendered
return [value, self.base_units]
return [None, self.base_units]