from kivymd.app import MDApp
from kivy.lang import Builder
from kivymd.uix.screenmanager import MDScreenManager
from kivymd.uix.screen import MDScreen
from kivymd.uix.pickers import MDDockedDatePicker
from kivy.properties import StringProperty
from kivy.metrics import dp

kv = """
<LabelScreen@MDScreen>:
    md_bg_color: self.theme_cls.backgroundColor
    MDLabel:
        text: root.manager.date  # display the date
        halign: 'center'
    MDButton:
        pos_hint: {'center_x': .5, 'bottom': 1 }
        on_release: root.manager.current = 'date screen'

        MDButtonText:
            text: "Change Screen"

<DateScreen>:
    md_bg_color: self.theme_cls.backgroundColor
    MDTextField:
        id: field
        mode: "outlined"
        pos_hint: {'center_x': .5, 'center_y': .85}
        size_hint_x: .5
        on_focus: root.show_date_picker(self.focus)

        MDTextFieldHintText:
            text: "Docked date picker"

        MDTextFieldHelperText:
            text: "MM/DD/YYYY"
            mode: "persistent"

        MDTextFieldTrailingIcon:
            icon: "calendar"

    MDButton:
        pos_hint: {'center_x': .5, 'bottom': 1 }
        on_release: root.manager.current = 'label screen'

        MDButtonText:
            text: "Change Screen"


MDBoxLayout:
    orientation: 'vertical'
    md_bg_color: self.theme_cls.backgroundColor
    MDLabel:
        text: 'Share data between two screens'
        size_hint_y: None
        height: dp(30)
        halign: 'center'
    SharedScreenManager:
        DateScreen:
            name: 'date screen'
        LabelScreen:
            name: 'label screen'
"""


class SharedScreenManager(MDScreenManager):
    date = StringProperty()  # create a kivy property to share between the screens


class DateScreen(MDScreen):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.date_dialog = None # used to hold the date picker

    def show_date_picker(self, focus):
        if not focus:
            return
        self.date_dialog = MDDockedDatePicker()
        # You have to control the position of the date picker dialog yourself.
        self.date_dialog.pos = [
            self.ids.field.center_x - self.date_dialog.width / 2,
            self.ids.field.y - (self.date_dialog.height + dp(32)),
        ]
        self.date_dialog.bind(on_ok=self.on_date_selected)
        self.date_dialog.bind(on_cancel=lambda x: self.date_dialog.dismiss())
        self.date_dialog.open()

    def on_date_selected(self, selected):
        date = selected.get_date()[0].strftime('%m/%d/%Y')
        self.manager.date = date
        self.ids.field.text = date
        self.date_dialog.dismiss()


class SharedDataApp(MDApp):
    def build(self):
        self.theme_cls.primary_palette = "Olive"
        return Builder.load_string(kv)


SharedDataApp().run()