Why isn't KIVY apk built for android?

Question

Android

When building the application, everything seems to be working fine. When installed on the phone, at startup, Loading appears ... and disappears. Why can't I understand?!

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.core.window import Window
from kivy.clock import Clock
from requests import get, post


Window.size = (360, 480)
Window.clearcolor = (0, 0.17, 0.55, 1)


notice_list = []
try:
    with open('f.txt', 'r') as f:
        file = f.readlines()
        department = file[0].replace('\n', '')
        otk = file[1].replace('\n', '')
except:
    department = None
    otk = None

buttons = """
        Button:
            id: back
            text: 'ВОЗВРАЩЕНИЕ ЗАКАЗА НА ДОРАБОТКУ'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.server('back', False)
""" if otk == "otk" or otk == None else ''

Builder.load_string(f"""
<MenuScreen>:
    BoxLayout:
        orientation: 'vertical'
        padding: 5, 5
        spacing: 5

        Button:
            text: 'УВЕДОМЛЕНИЯ'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.clear()
            Image:
                source: 'bell-ring.png'
                id: bell
                opacity: 0
                size_hint: None, None
                size: 30, 30
                center_x: 330
                center_y: 450
        Button:
            text: 'ЗАКАЗЫ В РАБОТЕ'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.manager.current = 'foto'
        Button:
            text: 'СКАНИРОВАНИЕ QR'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.manager.current = 'scan'

<AllScreen>:
    BoxLayout:
        orientation: 'vertical'
        Button:
            text: 'KM'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.save('km')
        Button:
            text: 'KMД'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.save('kmd')
        Button:
            text: 'ТМЦ'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.save('tmc')
        Button:
            text: 'ЗАГОТОВКА'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.save('zagatovka')
        Button:
            text: 'СБОРКА'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.save('sborka')
        Button:
            text: 'СВАРКА'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.save('svarka')
        Button:
            text: 'УПАКОВКА'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.save('upakovka')

<All2Screen>:
    BoxLayout:
        orientation: 'vertical'
        Button:
            text: 'Производство'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.save('not_otk')
        Button:
            text: 'ОТК'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.save('otk')

<FotoScreen>:
    BoxLayout:
        orientation: 'vertical'
        Button:
            background_color: (0, 0.17, 0.55, 1)
            on_press: root.manager.current = 'menu'
            Image:
                source: 'demo_01.png'
                size: self.parent.size

<ScanScreen>:
    BoxLayout:
    #:import ZBarCam kivy_garden.zbarcam.ZBarCam
        id: box
        orientation: 'vertical'
        padding: 5, 5
        spacing: 5
        ZBarCam:
            id: qrcodecam
        Label:
            size_hint: None, None
            size: self.texture_size[0], 50
            id: qr_text
            text: ' '

        Button:
            text: 'РАБОТА НАЧАТА'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.server('start', True)
        Button:
            text: 'РАБОТА ПРИОСТАНОВЛЕНА/ВОЗОБНОВЛЕНА'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.server('stop', True)
        Button:
            text: 'ОБРАТНО В МЕНЮ'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.manager.current = 'menu'
        Button:
            text: 'ОТСКАНИРОВАТЬ'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.get_qr()
        Button:
            text: 'РАБОТА ЗАКОНЧЕНА'
            background_color: (0, 0.12, 0.52, 1)
            on_press: root.server('end', True)
""" + buttons)


class MenuScreen(Screen):
    def clear(self):
        global notice_list
        notice_list.clear()


class AllScreen(Screen):
    def save(self, select):
        global department
        department = select

        with open('f.txt', 'w') as f:
            f.write(f'{department}\n')

        App.get_running_app().root.current = 'select_otk'

class All2Screen(Screen):
    def save(self, select):
        global otk
        otk = select

        with open('f.txt', 'a') as f:
            f.write(f'{otk}\n')

        if otk != 'otk':
            scan_screen = App.get_running_app().root.get_screen('scan')

            scan_screen.ids['box'].remove_widget(scan_screen.ids['back'])

        App.get_running_app().root.current = 'menu'

class FotoScreen(Screen):
    pass

class ScanScreen(Screen):
    def server(self, command, check_otk):
        r = get(f'http://code-factory.site/api/give_csrf')
        csrf = r.text.split('=')[-1][1:-2]
        cookies = r.cookies.get_dict()

        add = ''
        if check_otk and otk == 'otk':
            add = '_otk'

        post(f'http://code-factory.site/api/{command}{add}/{department}',
             data = {'id': self.ids['qr_text'].text.split('\n')[0], 'csrfmiddlewaretoken': csrf},
             cookies = cookies)

        self.ids['qr_text'].text = ''

    def get_qr(self):
        qr = ''.join([symbol.data.decode('utf-8') for symbol in self.ids['qrcodecam'].symbols])

        self.ids['qr_text'].text = qr


def get_notice(_):
    for i in get(f'http://code-factory.site/api/notice/{department}').text.split(','):
        if i != '':
            notice_list.append(i)

    if len(notice_list) > 0:
        App.get_running_app().root.get_screen('menu').ids['bell'].opacity = 1
    else:
        App.get_running_app().root.get_screen('menu').ids['bell'].opacity = 0


class MainApp(App):
    def build(self):
        sm = ScreenManager()

        sm.add_widget(MenuScreen(name='menu'))
        sm.add_widget(ScanScreen(name='scan'))
        sm.add_widget(FotoScreen(name='foto'))
        sm.add_widget(AllScreen(name='all'))
        sm.add_widget(All2Screen(name='select_otk'))

        if department == None or department == 'None' or otk == None or otk == 'None':
            sm.current = 'all'
        else:
            sm.current = 'menu'

        return sm


if __name__=='__main__':
    Clock.schedule_interval(get_notice, 3)

    MainApp().run()

Answer 1

Do you want to provide logs?
adb logcat | grep python