Merge pull request kivy#3890 from kivy/window_focus

turn Window.focus into a read-only property

Author: dessant

kivy/core/window/__init__.py

@@ -295,6 +295,7 @@ class WindowBase(EventDispatcher):
     _modifiers = ListProperty([])
     _rotation = NumericProperty(0)
     _clearcolor = ObjectProperty([0, 0, 0, 1])
+    _focus = BooleanProperty(True)
 
     children = ListProperty([])
     '''List of the children of this window.
@@ -599,12 +600,15 @@ def _get_effective_size(self):
     defaults to True.
     '''
 
-    focus = BooleanProperty(True)
-    '''Set whether or not the window currently has focus.
+    def _get_focus(self):
+        return self._focus
 
-    .. versionadded::1.9.1
+    focus = AliasProperty(_get_focus, None, bind=('_focus',))
+    '''Check whether or not the window currently has focus.
 
-    :attr:`focus` is a :class:`~kivy.properties.BooleanProperty and
+    .. versionadded:: 1.9.1
+
+    :attr:`focus` is a read-only :class:`~kivy.properties.AliasProperty and
     defaults to True.
     '''
 

kivy/core/window/window_sdl2.py

@@ -472,6 +472,12 @@ def _mainloop(self):
                 if Config.getboolean('kivy', 'pause_on_minimize'):
                     self.do_pause()
 
+            elif action == 'windowfocusgained':
+                self._focus = True
+
+            elif action == 'windowfocuslost':
+                self._focus = False
+
             elif action == 'windowenter':
                 self.dispatch('on_cursor_enter')
 
@@ -559,12 +565,6 @@ def _mainloop(self):
                 text = args[0]
                 self.dispatch('on_textinput', text)
 
-            elif action == 'windowfocusgained':
-                self.focus = True
-
-            elif action == 'windowfocuslost':
-                self.focus = False
-
             # unhandled event !
             else:
                 Logger.trace('WindowSDL: Unhandled event %s' % str(event))