Kivy Widget for showing/hidding content.

visiblecontainer.py

from kivy.uix.relativelayout import RelativeLayout
from kivy.properties import BooleanProperty, NumericProperty
from kivy.animation import Animation


class VisibleContainer(RelativeLayout):
    visible = BooleanProperty(True)
    animated = BooleanProperty(False)
    duration = NumericProperty(0.2)
    capture = BooleanProperty(False)

    def __init__(self, **kwargs):
        self.saved_children = []
        self.anim = None
        super().__init__(**kwargs)

    def add_widget(self, child):
        if child not in self.saved_children:
            self.saved_children.append(child)
        if not self.visible:
            return
        super().add_widget(child)

    def remove_widget(self, child):
        if child in self.saved_children:
            self.saved_children.remove(child)
        if not self.visible:
            return
        super().remove_widget(child)

    def _populate(self):
        self._unpopulate()
        for child in self.saved_children:
            super().add_widget(child)

    def _unpopulate(self):
        for child in self.saved_children:
            super().remove_widget(child)

    def on_visible(self, *largs):
        if self.visible:
            self._populate()
            if self.animated:
                self.fade_in()
        else:
            if self.animated:
                self.fade_out()
            else:
                self._unpopulate()

    def cancel_anim(self):
        if self.anim:
            self.anim.cancel_all(self)

    def fade_in(self):
        self.cancel_anim()
        self._populate()
        self.opacity = 0
        self.anim = Animation(opacity=1, duration=self.duration)
        self.anim.start(self)

    def fade_out(self):
        self.cancel_anim()
        self._populate()
        self.opacity = 1
        self.anim = Animation(opacity=0, duration=self.duration)
        self.anim.bind(on_complete=self.on_fade_out_complete)
        self.anim.start(self)

    def on_fade_out_complete(self, *largs):
        for child in self.saved_children:
            super().remove_widget(child)

    def on_touch_down(self, touch):
        ret = super().on_touch_down(touch)
        return ret or (self.capture and self.visible)

    def on_touch_move(self, touch):
        ret = super().on_touch_move(touch)
        return ret or (self.capture and self.visible)

    def on_touch_up(self, touch):
        ret = super().on_touch_up(touch)
        return ret or (self.capture and self.visible)