Restructured repository

sbapp/kivymd/uix/screenmanager.py

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+"""
+Components/ScreenManager
+========================
+
+.. versionadded:: 1.0.0
+
+:class:`~kivy.uix.screenmanager.ScreenManager` class equivalent.
+If you want to use Hero animations you need to use :class:`~kivymd.uix.screenmanager.MDScreenManager`
+not :class:`~kivy.uix.screenmanager.ScreenManager` class.
+"""
+
+from kivy.clock import Clock
+from kivy.properties import ListProperty, StringProperty
+from kivy.uix.screenmanager import ScreenManager
+
+from kivymd.uix.hero import MDHeroFrom
+
+
+class MDScreenManager(ScreenManager):
+    current_hero = StringProperty(None)
+    """
+    The name of the current tag for the :class:`~kivymd.uix.hero.MDHeroFrom` and
+    :class:`~kivymd.uix.hero.MDHeroTo` objects that will be animated when
+    animating the transition between screens.
+
+    See the `Hero <https://kivymd.readthedocs.io/en/latest/components/hero/>`_
+    module documentation for more information about creating and using Hero animations.
+
+    :attr:`current_hero` is an :class:`~kivy.properties.StringProperty`
+    and defaults to `None`.
+    """
+
+    # Collection of `MDHeroFrom` objects on all screens of the current
+    # screen manager.
+    _heroes_data = ListProperty()
+
+    def __init__(self, **kwargs):
+        super().__init__(**kwargs)
+        Clock.schedule_once(self.check_transition)
+
+    def check_transition(self, *args) -> None:
+        """Sets the default type transition."""
+
+        from kivymd.uix.transition.transition import MDTransitionBase
+
+        if not issubclass(self.transition.__class__, MDTransitionBase):
+            from kivymd.uix.transition import MDSlideTransition
+
+            self.transition = MDSlideTransition()
+
+    def get_hero_from_widget(self) -> None:
+        """
+        Get an :class:`~kivymd.uix.hero.MDHeroTo` object with the
+        :attr:`~current_hero` tag.
+        """
+
+        hero_from_widget = None
+
+        for hero_widget in self._heroes_data:
+            if isinstance(hero_widget, MDHeroFrom) or issubclass(
+                hero_widget.__class__, MDHeroFrom
+            ):
+                if hero_widget.tag == self.current_hero:
+                    hero_from_widget = hero_widget
+                    break
+
+        return hero_from_widget
+
+    def add_widget(self, widget, *args, **kwargs):
+        super().add_widget(widget, *args, **kwargs)
+        Clock.schedule_once(lambda x: self._create_heroes_data(widget))
+
+    def _create_heroes_data(self, widget):
+        def find_hero_widget(child_widget):
+            widget_hero = None
+
+            for w in child_widget.children:
+                if isinstance(w, MDHeroFrom) or issubclass(
+                    w.__class__, MDHeroFrom
+                ):
+                    self._heroes_data.append(w)
+                find_hero_widget(w)
+
+            return widget_hero
+
+        for child in widget.children:
+            if isinstance(child, MDHeroFrom) or issubclass(
+                child.__class__, MDHeroFrom
+            ):
+                self._heroes_data.append(child)
+            else:
+                find_hero_widget(child)