refactor some of examples

examples/reorderable_stacklayout.py

@@ -1,7 +1,7 @@
 '''
 When you want to make a :class:`kivy.uix.stacklayout.StackLayout` re-orderable, you may want to disable the
-``size_hint`` of each child, or may want to limit the maximum size of each child, otherwise the layout will be messed
-up. You can confirm that by commenting/uncommenting the part of ``SampleApp.on_start()``.
+``size_hint`` of its children, or may want to limit the maximum size of them, otherwise the layout will be messed
+up. You can confirm that by commenting/uncommenting the specified part of ``SampleApp.on_start()``.
 '''
 
 from kivy.lang import Builder

examples/using_other_widget_as_an_emitter.py

@@ -39,7 +39,7 @@
         size_hint_x: .1
 
     # Put the board inside a RelativeLayout just to confirm the coordinates are properly transformed.
-    # It's not necessary for this example to work though.
+    # This is not necessary for this example to work.
     RelativeLayout:
         GridLayout:
             id: board
@@ -88,10 +88,13 @@ class Deck(Label):
     def on_touch_down(self, touch):
         if self.collide_point(*touch.opos):
             if (text := next(self.text_iter, None)) is not None:
-                card = Card(text=text, size=self.board.children[0].size)
+                card = Card(text=text, size=self._get_cell_size())
                 card.start_dragging_from_others_touch(self, touch)
             return True
 
+    def _get_cell_size(self):
+        return self.board.children[0].size
+
 
 class SampleApp(App):
     def build(self):