clayote · August 29, 2015 14:25 · Jul 21, 2015 · Jul 21, 2015
diff --git a/trigger_decorator.py b/trigger_decorator.py
@@ -1,31 +1,31 @@
 from kivy.event import EventDispatcher
 from kivy.clock import Clock
+from functools import partial
 
 
-# this works fine
-class Burger(EventDispatcher):
-    def flip(self, *args):
-        pass
-
-    @property
-    def _trigger_flip(self):
-        if not hasattr(self, '_real_trigger_flip'):
-            self._real_trigger_flip = Clock.create_trigger(self.flip)
-        return self._real_trigger_flip
-
+class trigger(object):
+    """Make a trigger from a method outside of your class's __init__."""
+    def __init__(self, func):
+        self.func = func
 
-# this keeps triggering the method on unexpected objects,
-# including many that shouldn't have the method at all, eg. floats
-def get_trigger(obj, fun):
-    n = '_real_trigger_' + fun.__name__
-    if not hasattr(obj, n):
-        setattr(obj, n, Clock.create_trigger(fun))
-    return getattr(obj, n)
+    def __get__(self, instance, owner=None):
+        if instance is None:
+            # EventDispatcher iterates over its attributes before it instantiates.
+            # Don't try making any trigger in that case.
+            return
+        if not hasattr(self, '_trig'):
+            self._trig = Clock.create_trigger(
+                partial(self.func, instance), 0
+            )
+        return self._trig
 
-trigger = lambda fun: property(fget=lambda self: get_trigger(self, fun))
 
-class Fries(EventDispatcher):
-    def fry(self, *args):
+class Salad(EventDispatcher):
+    def toss(self, *args):
         pass
-
-    _trigger_fry = trigger(fry)
+    _trigger_toss = trigger(toss)
+
+    @trigger
+    def _trigger_serve(self, *args):
+        # for when a method should only be usable via trigger
+        pass
diff --git a/trigger_decorator.py b/trigger_decorator.py
@@ -0,0 +1,31 @@
+from kivy.event import EventDispatcher
+from kivy.clock import Clock
+
+
+# this works fine
+class Burger(EventDispatcher):
+    def flip(self, *args):
+        pass
+
+    @property
+    def _trigger_flip(self):
+        if not hasattr(self, '_real_trigger_flip'):
+            self._real_trigger_flip = Clock.create_trigger(self.flip)
+        return self._real_trigger_flip
+
+
+# this keeps triggering the method on unexpected objects,
+# including many that shouldn't have the method at all, eg. floats
+def get_trigger(obj, fun):
+    n = '_real_trigger_' + fun.__name__
+    if not hasattr(obj, n):
+        setattr(obj, n, Clock.create_trigger(fun))
+    return getattr(obj, n)
+
+trigger = lambda fun: property(fget=lambda self: get_trigger(self, fun))
+
+class Fries(EventDispatcher):
+    def fry(self, *args):
+        pass
+
+    _trigger_fry = trigger(fry)