Как пользоваться screen manager в KivyMD?

Question

[SashaN69]

Как правильно пользоваться screen manager в KivyMD?

Answer 1

[dadasay]

Думаю начать стоит с этого документация

Comments

[SashaN69]

В простом kivy всё нормально работает,а в kivymd ошибка

[dadasay]

Ну тогда ошибку в студию

[SashaN69]

ValueError: KivyMD: App object must be initialized before loading root widget

[SashaN69]

from kivymd.app import MDApp
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
import kod
def human_index(m, h):
    hindex = str(round(m / (h * h), 1) )

    return {'hindex': hindex}

class MenuScreen(Screen):

    def calculate(self):
        try:
            mass = float(self.second.text)
            heigth = float(self.first.text)

            human_i = human_index(mass, heigth)

            gets = human_i.get('hindex')

            self.third.text = "Ваш результат: " + str(gets)
            self.first.text = ""
            self.second.text = ""

            if 16.5 > float(gets):
                self.fourth.text = "Крайний недостаток веса"
            elif  16.5 < float(gets)  < 18.4:
                self.fourth.text = "Недостаток веса"
            elif  18.5 < float(gets)  < 24.9:
                self.fourth.text = "Нормальный вес"
            elif  25 < float(gets)  < 30:
                self.fourth.text = "Избыточная масса"
            elif  30.01 < float(gets)  < 34.9:
                self.fourth.text = "Ожирение(Клас I)"
            elif  35 < float(gets)  < 40:
                self.fourth.text = "Ожирение(Клас II)"
            elif  40 < float(gets) < 70:
                self.fourth.text = "Ожирение(Клас III)"
            elif  71 < float(gets):
                self.fourth.text = "А ты шутник"

        except:
            self.third.text = "Вы не ввели число"
            self.first.text = ""
            self.second.text = ""
            self.fourth.text = "----------"


class SettingsScreen(Screen):
    pass
sm = ScreenManager()
sm.add_widget(SettingsScreen(name='settings'))
sm.add_widget(MenuScreen(name='menu'))
class Myapp(MDApp):
    def __init__(self, **kwargs):
        self.title = "My app"
        super().__init__(**kwargs)
    def build(self):
        return sm





if __name__ == "__main__":
    Myapp().run()

[SashaN69]

dadasay, kv файл

from kivy.lang import Builder

Builder.load_string("""
:
GridLayout:
first: text_mass
second: text_heigth
third: label
fourth: labels
rows: 5
padding: 30
spacing: 5

MDLabel:
id: label
size_hint: 1, 0.4
font_name: "data/fonts/RobotoMono-Regular.ttf"
text: 'Веддите данные'
font_size: '30sp'

MDLabel:
id: labels
font_name: "data/fonts/RobotoMono-Regular.ttf"
text: '----------'
size_hint: 1, 0.2
font_size: '24sp'

MDTextField:
id: text_mass
hint_text: 'Введите рост'
size_hint: 1, 0.2
multiline: False
font_size: '20sp'

MDTextField:
id: text_heigth
hint_text: 'Введите вес'
size_hint: 1, 0.2
multiline: False
font_size: '20sp'

FloatLayout:

MDFillRoundFlatButton:
size_hint: 0.8, 0.22
font_size: '30sp'
background_color: .73, .05, .05, 1
font_name: "data/fonts/RobotoMono-Regular.ttf"
pos_hint: {'center_x': 0.5, 'y': 0.5}
text: 'Расчитать'

on_release:
root.calculate()

MDFillRoundFlatButton:
size_hint: 0.8, 0.2
spacing:
background_color: .73, .05, .05, 1
font_size: '30sp'
font_name: "data/fonts/RobotoMono-Regular.ttf"
pos_hint: {'center_x': 0.5, 'y': 0.28}
text: 'Настройки'

on_release:
""")

[dadasay]

Пример