Here's my working custom field and widget:
class LatLongWidget(forms.MultiWidget):
"""
A Widget that splits Point input into two latitude/longitude boxes.
"""
def __init__(self, attrs=None, date_format=None, time_format=None):
widgets = (forms.TextInput(attrs=attrs),
forms.TextInput(attrs=attrs))
super(LatLongWidget, self).__init__(widgets, attrs)
def decompress(self, value):
if value:
return tuple(reversed(value.coords))
return (None, None)
class LatLongField(forms.MultiValueField):
widget = LatLongWidget
srid = 4326
default_error_messages = {
'invalid_latitude' : _('Enter a valid latitude.'),
'invalid_longitude' : _('Enter a valid longitude.'),
}
def __init__(self, *args, **kwargs):
fields = (forms.FloatField(min_value=-90, max_value=90),
forms.FloatField(min_value=-180, max_value=180))
super(LatLongField, self).__init__(fields, *args, **kwargs)
def compress(self, data_list):
if data_list:
# Raise a validation error if latitude or longitude is empty
# (possible if LatLongField has required=False).
if data_list[0] in validators.EMPTY_VALUES:
raise forms.ValidationError(self.error_messages['invalid_latitude'])
if data_list[1] in validators.EMPTY_VALUES:
raise forms.ValidationError(self.error_messages['invalid_longitude'])
# SRID=4326;POINT(1.12345789 1.123456789)
srid_str = 'SRID=%d'%self.srid
point_str = 'POINT(%f %f)'%tuple(reversed(data_list))
return ';'.join([srid_str, point_str])
return None
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