class ShareCalendar(MDApp):
    def build(self):
        return Builder.load_file('sharecalendar.kv')

    def show_date_picker(self):
        date_dialog = MDDatePicker()
        date_dialog.bind(on_save=self.on_save, on_cancel=self.on_cancel)
        date_dialog.open()

    def on_save(self, instance, value, date_range):
        self.root.ids.date_button.text = str(value)

    def on_cancel(self, instance, value):
        pass