datepicker for kivy

datepicker.py

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout

KV = """
#:import Calendar calendar.Calendar

<Day@Button>:
    datepicker: self.parent.datepicker
    color: [1,1,1,1]
    background_color: root.color if self.text != "" else [0,0,0,0]
    disabled: True if self.text == "" else False
    on_release:
        root.datepicker.picked = [int(self.text), root.datepicker.month, root.datepicker.year]

<Week@BoxLayout>:
    datepicker: root.parent
    weekdays: ["","","","","","",""]
    Day:
        text: str(root.weekdays[0])
    Day:
        text: str(root.weekdays[1])
    Day:
        text: str(root.weekdays[2])
    Day:
        text: str(root.weekdays[3])
    Day:
        text: str(root.weekdays[4])
    Day:
        text: str(root.weekdays[5])
    Day:
        text: str(root.weekdays[6])

<WeekDays@BoxLayout>:
    Label:
        text: "Mon"
    Label:
        text: "Tue"
    Label:
        text: "Wed"
    Label:
        text: "Thu"
    Label:
        text: "Fri"
    Label:
        text: "Sat"
    Label:
        text: "Sun"

<NavBar@BoxLayout>:
    datepicker: self.parent
    Spinner:
        values: root.datepicker.months
        text: root.datepicker.months[root.datepicker.month-1]
        on_text:
            root.datepicker.month = root.datepicker.months.index(self.text)+1
    Spinner:
        values: [str(i) for i in range(1970,2100)]
        text: str(root.datepicker.year)
        on_text:
            root.datepicker.year = int(self.text)
    Widget:
    Button:
        text: "<"
        on_release:
            if root.datepicker.month == 1 and spin.text == "Month": root.datepicker.year -= 1
            if spin.text == "Month": root.datepicker.month = 12 if root.datepicker.month == 1 else root.datepicker.month - 1
            if spin.text == "Year": root.datepicker.year -= 1
    Spinner:
        id: spin
        values: ["Month","Year"]
        text: "Month"

    Button:
        text: ">"
        on_release:
            if root.datepicker.month == 12 and spin.text == "Month": root.datepicker.year += 1
            if spin.text == "Month": root.datepicker.month = 1 if root.datepicker.month == 12 else root.datepicker.month + 1
            if spin.text == "Year": root.datepicker.year += 1

<DatePicker@BoxLayout>:
    year: 2020
    month: 1
    picked: ["","",""]
    months: ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
    calendar: Calendar()
    days: [(i if i > 0 else "") for i in self.calendar.itermonthdays(self.year, self.month)] + [""] * 14
    orientation: "vertical"
    NavBar:
    WeekDays:
    Week:
        weekdays: root.days[0:7]
    Week:
        weekdays: root.days[7:14]
    Week:
        weekdays: root.days[14:21]
    Week:
        weekdays: root.days[21:28]
    Week:
        weekdays: root.days[28:35]
    Week:
        weekdays: root.days[35:]
    Label:
        text: "" if root.picked == ["","",""] else "{}/{}-{}".format(root.picked[0], root.picked[1], root.picked[2])
"""

class DatePicker(BoxLayout):
    pass

Builder.load_string(KV)

class MyApp(App):
    def build(self):
        return DatePicker()

MyApp().run()