/GUI/Generic/GRadioGroups.py

 1#
 2#		Python GUI - Radio groups - Generic
 3#
 4
 5from Properties import Properties, overridable_property
 6from Actions import Action
 7
 8class RadioGroup(Properties, Action):
 9    """A RadioGroup coordinates a group of RadioButtons.
10    It has a 'value' property which is equal to the value
11    of the currently selected RadioButton. It may be given
12    an action procedure to execute when its value changes.
13    
14    Operations:
15        iter(group)
16            Returns an iterator over the items of the group.
17    """
18    
19    value = overridable_property('value', """The value of the currently
20        selected radio button.""")
21
22    _items = None
23    _value = None
24
25    def __init__(self, items = [], **kwds):
26        Properties.__init__(self, **kwds)
27        self._items = []
28        self.add(*items)
29    
30    #
31    #   Operations
32    #
33    
34    def __iter__(self):
35        return iter(self._items)
36
37    #
38    #		Properties
39    #
40
41    def get_value(self):
42        return self._value
43
44    def set_value(self, x):
45        if self._value <> x:
46            self._value = x
47            self._value_changed()
48            self.do_action()
49    
50    #
51    #		Adding and removing items
52    #
53
54    def add(self, *items):
55        "Add one or more RadioButtons to this group."
56        for item in items:
57            item.group = self
58
59    def remove(self, *items):
60        "Remove one or more RadioButtons from this group."
61        for item in items:
62            item.group = None
63
64    def _add(self, item):
65        self._items.append(item)
66        self._item_added(item)
67    
68    def _remove(self, item):
69        self._items.remove(item)
70        self._item_removed(item)
71    
72    def _item_added(self, item):
73        raise NotImplementedError
74
75    def _item_removed(self, item):
76        raise NotImplementedError
77
78    def _value_changed(self):
79        raise NotImplementedError