newforms: Implemented NullBooleanField and NullBooleanSelect

git-svn-id: http://code.djangoproject.com/svn/django/trunk@4411 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/newforms/fields.py

@@ -4,7 +4,7 @@ Field classes
 
 from django.utils.translation import gettext
 from util import ErrorList, ValidationError, smart_unicode
-from widgets import TextInput, PasswordInput, HiddenInput, MultipleHiddenInput, CheckboxInput, Select, SelectMultiple
+from widgets import TextInput, PasswordInput, HiddenInput, MultipleHiddenInput, CheckboxInput, Select, NullBooleanSelect, SelectMultiple
 import datetime
 import re
 import time
@@ -15,7 +15,7 @@ __all__ = (
     'DEFAULT_TIME_INPUT_FORMATS', 'TimeField',
     'DEFAULT_DATETIME_INPUT_FORMATS', 'DateTimeField',
     'RegexField', 'EmailField', 'URLField', 'BooleanField',
-    'ChoiceField', 'MultipleChoiceField',
+    'ChoiceField', 'NullBooleanField', 'MultipleChoiceField',
     'ComboField', 'MultiValueField',
     'SplitDateTimeField',
 )
@@ -317,6 +317,16 @@ class BooleanField(Field):
         super(BooleanField, self).clean(value)
         return bool(value)
 
+class NullBooleanField(BooleanField):
+    """
+    A field whose valid values are None, True and False. Invalid values are
+    cleaned to None.
+    """
+    widget = NullBooleanSelect
+
+    def clean(self, value):
+        return {True: True, False: False}.get(value, None)
+
 class ChoiceField(Field):
     def __init__(self, choices=(), required=True, widget=Select, label=None, initial=None):
         if isinstance(widget, type):

django/newforms/widgets.py

@@ -5,13 +5,14 @@ HTML Widget classes
 __all__ = (
     'Widget', 'TextInput', 'PasswordInput', 'HiddenInput', 'MultipleHiddenInput',
     'FileInput', 'Textarea', 'CheckboxInput',
-    'Select', 'SelectMultiple', 'RadioSelect', 'CheckboxSelectMultiple',
+    'Select', 'NullBooleanSelect', 'SelectMultiple', 'RadioSelect', 'CheckboxSelectMultiple',
     'MultiWidget', 'SplitDateTimeWidget',
 )
 
 from util import flatatt, StrAndUnicode, smart_unicode
 from django.utils.datastructures import MultiValueDict
 from django.utils.html import escape
+from django.utils.translation import gettext
 from itertools import chain
 
 try:
@@ -151,6 +152,25 @@ class Select(Widget):
         output.append(u'</select>')
         return u'\n'.join(output)
 
+class NullBooleanSelect(Select):
+    """
+    A Select Widget intended to be used with NullBooleanField.
+    """
+    def __init__(self, attrs=None):
+        choices = ((u'1', gettext('Unknown')), (u'2', gettext('Yes')), (u'3', gettext('No')))
+        super(NullBooleanSelect, self).__init__(attrs, choices)
+
+    def render(self, name, value, attrs=None, choices=()):
+        try:
+            value = {True: u'2', False: u'3', u'2': u'2', u'3': u'3'}[value]
+        except KeyError:
+            value = u'1'
+        return super(NullBooleanSelect, self).render(name, value, attrs, choices)
+
+    def value_from_datadict(self, data, name):
+        value = data.get(name, None)
+        return {u'2': True, u'3': False, True: True, False: False}.get(value, None)
+
 class SelectMultiple(Widget):
     def __init__(self, attrs=None, choices=()):
         # choices can be any iterable