Updated code for new Python 3 support in Kivy and improved code style.

quizzer.kv

@@ -5,7 +5,7 @@ ScreenManager:
             orientation: 'vertical'
             Label:
                 text: 'Choose a topic:'
-                font_size: '24sp'
+                font_size: sp(24)
             BoxLayout:
                 orientation: 'horizontal'
                 Widget:
@@ -19,7 +19,7 @@ ScreenManager:
                 Label:
                     id: gui_label
                     text: 'Graphical User Interfaces'
-                    size_hint: (None, 1)
+                    size_hint: (None, 1.0)
                     size: self.texture_size
                 Widget:
             BoxLayout:
@@ -35,7 +35,7 @@ ScreenManager:
                 Label:
                     id: color_label
                     text: 'RGBA Quadruples'
-                    size_hint: (None, 1)
+                    size_hint: (None, 1.0)
                     size: self.texture_size
                 Widget:
             BoxLayout:
@@ -51,7 +51,7 @@ ScreenManager:
                 Label:
                     id: tree_label
                     text: 'Containment Hierarchies'
-                    size_hint: (None, 1)
+                    size_hint: (None, 1.0)
                     size: self.texture_size
                 Widget:
             BoxLayout:
@@ -65,7 +65,7 @@ ScreenManager:
                         root.current = 'quiz'
                 Widget:
             Widget:
-                size_hint: (1, 0.5)
+                size_hint: (1.0, 0.5)
     Screen:
         name: 'quiz'
         BoxLayout:
@@ -79,12 +79,12 @@ ScreenManager:
                     root.current = 'settings'
             Label:
                 text: 'Do you know…'
-                font_size: '24sp'
+                font_size: sp(24)
                 size_hint: (1, None)
                 size: (self.texture_size[0] + 64, self.texture_size[1] + 64)
             Label:
                 text: (app.questions[-1] if len(app.questions) > 0 else app.DEFAULT_QUESTION)[0] if not app.paused else ('Correct!' if app.correct else 'Incorrect!')
-                color: (0, 0, 0.75, 1) if not app.paused else ((0, 1, 0, 1) if app.correct else (0.5, 0, 0, 1))
+                color: (0.0, 0.0, 0.75, 1.0) if not app.paused else ((0.0, 1.0, 0.0, 1.0) if app.correct else (0.5, 0.0, 0.0, 1.0))
             GridLayout:
                 rows: 2
                 Button:
@@ -108,25 +108,25 @@ ScreenManager:
 <Screen>:
     canvas.before:
         Color:
-            rgba: (1, 1, 1, 1)
+            rgba: (1.0, 1.0, 1.0, 1.0)
         Rectangle:
             pos: self.pos
             size: self.size
 
 # All labels are blue.
 <Label>:
-    color: (0, 0, 0.75, 1)
+    color: (0.0, 0.0, 0.75, 1.0)
 
 # All checkboxes are blue.
 <CheckBox>:
     canvas:
         Color:
-            rgba: (0, 0, 0.75, 1)
+            rgba: (0.0, 0.0, 0.75, 1.0)
         Rectangle:
-            source: 'atlas://data/images/defaulttheme/checkbox{radio}{disabled}{on}'.format(radio=('_radio' if self.group else ''), disabled=('_disabled' if self.disabled else ''), on=('_on' if self.active else '_off'))
+            source: f'atlas://data/images/defaulttheme/checkbox{"_radio" if self.group else ""}{"_disabled" if self.disabled else ""}{"_on" if self.active else "_off"}'
             size: sp(32), sp(32)
             pos: int(self.center_x - sp(16)), int(self.center_y - sp(16))
 
 # All buttons have white text.
 <Button>:
-    color: (1, 1, 1, 1)
+    color: (1.0, 1.0, 1.0, 1.0)