如何从 KivyMD 中的 MDTextField 获取用户输入

Question

当我尝试将用户输入的文本输入到 MDTextField 中时，我不断收到属性错误，尝试了我能想到的一切，研究过但什么也得不到。 拜托我需要你的帮忙。

我尝试使用self.root.ids.MyId.text这个参数获取文本

这是我得到的错误：

File "C:/Users/user/Documents/KmD/Webma/main_webma.py", line 120, in login
     email_addr = self.root.ids.email.text
   File "kivy\properties.pyx", line 864, in kivy.properties.ObservableDict.__getattr__
 AttributeError: 'super' object has no attribute '__getattr__'

这是我的 main.py 代码

from kivymd.app import MDApp
from kivy.clock import Clock
from kivy.lang import Builder
from home_page_strings import toolbar
import sqlite3
from kivy.uix.screenmanager import Screen, ScreenManager
from kivymd.uix.picker import MDThemePicker
from kivy.uix.popup import Popup
from kivymd.uix.textfield import MDTextField


# calling of screen classes and addition to the screen_manager

class Friend1(Screen):
    pass


class WelcomeScreen(Screen):
    def __init__(self, **kwargs):
        super(WelcomeScreen, self).__init__(**kwargs)
        Clock.schedule_once(self.callNext, 5)

    def callNext(self, dt):
        self.manager.current = 'account'


class AccountScreen(Screen):
    pass


class HomeScreen(Screen):
    pass


class RoomScreen(Screen):
    pass


class ContactsScreen(Screen):
    pass


class CallsScreen(Screen):
    pass


class SettingsScreen(Screen):
    pass


class FaqScreen(Screen):
    pass


class InviteScreen(Screen):
    pass


manager = ScreenManager()
manager.add_widget(Friend1(name='friend1'))
manager.add_widget(HomeScreen(name='home'))
manager.add_widget(WelcomeScreen(name='welcome'))
manager.add_widget(RoomScreen(name='room'))
manager.add_widget(ContactsScreen(name='contacts'))
manager.add_widget(CallsScreen(name='calls'))
manager.add_widget(SettingsScreen(name='settings'))
manager.add_widget(FaqScreen(name='faq'))
manager.add_widget(InviteScreen(name='invite'))
manager.add_widget(AccountScreen(name='account'))


# end of call of screen classes and addition to screenmanager


class EMC_WebmaApp(MDApp):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

    # -------------------------- CODE FOR THE DATABASE ---------------------------------- #
    conn = sqlite3.connect('webma_database.db')
    cursor = conn.cursor()

    # cursor.execute('''CREATE TABLE users (
    #                 email text,
    #                 password integer
    #                 )''')

    def sign_up(self, cursor):
        cursor.execute('INSERT INTO users VALUES('', '')')

    conn.commit()
    conn.close()

    # -------------------------- END OF CODE FOR THE DATABASE ---------------------------------- #

    # BUILDER FUNCTION AND SCREEN
    def build(self):
        screen = Screen()

        # theme settings
        self.theme_cls.primary_palette = 'DeepPurple'
        self.theme_cls.theme_style = 'Dark'
        # end of theme declaration

        # loaded strings
        navigation_bar = Builder.load_string(toolbar)
        # end of loaded strings

        # addition of loaded strings to screen + return screen
        screen.add_widget(navigation_bar)

        return screen
        # end of addition

    # END OF BUILDER FUNCTION

    # USER VALIDATION FUNCTION

    def login(self):
        email_addr = self.root.ids.email.text

        if email_addr == str(''):
            print('Invalid Email Address')

    # END OF USER VALIDATION

    def change(self, dt):
        self.root.manager.current = 'home'

    # App theme manager
    def change_theme(self):
        picker = MDThemePicker()
        picker.open()

    # End of app theme manager

    # home page search bar
    def search_bar(self, dt):
        searchbar = Popup(
            title='Search',
            content=MDTextField(
                helper_text='Input values to be searched for',
                helper_text_mode='on_focus'
            ),
            auto_dismiss=True,
            # size_hint=(None, None),
            # size=(400, 98)
            size_hint=(0.7, 0.17),
            pos_hint={'center_x': 0.5, 'center_y': 0.8}
        )
        searchbar.open()


# APP RUN
if __name__ == '__main__':
    EMC_WebmaApp().run()
# WELL... THIS IS THE END OF EVERYTHING

然后是我尝试从中获取文本的字符串代码

    toolbar = '''
ScreenManager:
    WelcomeScreen:
    HomeScreen:
    RoomScreen:
    ContactsScreen
    CallsScreen:
    SettingsScreen:
    FaqScreen:
    InviteScreen:
    AccountScreen:
    Friend1:
    
<WelcomeScreen>:
    name: 'welcome'
    Image:
        source: 'logo.png'
        size_hint: 0.4, 0.4
        pos_hint: {'center_x': 0.5, 'center_y':0.6}
        
    MDLabel:
        text: 'Webma'
        halign: 'center'
        font_style: 'H3'
        color: (1, 1, 1, 1)
        pos_hint: {'center_x': 0.5, 'center_y':0.8}
        
    MDLabel:
        text: 'Powered by emc_codes'
        halign: 'center'
        bold: 'True'
        italic: True
        pos_hint: {'center_x': 0.5, 'center_y':0.1}
    
<HomeScreen>:
    name: 'home'
    
    NavigationLayout:
        ScreenManager:
            Screen:                        
                BoxLayout:               
                    orientation: 'vertical'
                    spacing: '8dp'

                    MDToolbar:
                        title: 'EMC_Webma'
                        left_action_items: [['menu', lambda x: navigation.set_state('open')]]
                        right_action_items: [['card-search', app.search_bar]]
                        elevation: 10
                        
                    ScrollView:
                        MDList:
                            TwoLineAvatarIconListItem:
                                text: 'Friend 1'
                                ImageLeftWidget: 
                                    source: 'einstein.jpg'
                                IconRightWidget:    
                                    icon: 'dots-vertical'
                
        MDNavigationDrawer:
            id: navigation
            
            BoxLayout:
                orientation: 'vertical'
                spacing: '8dp'
                padding: '8dp'
                            
                Image:
                    source: 'einstein.jpg'
                    
                MDLabel:
                    text: 'Enwerem Melvin Confidence'
                    font_style: 'Subtitle2'
                    size_hint_y: None
                    height: self.texture_size[1]
                    
                MDLabel:
                    text: 'enweremmelvinconfidence@gmail.com'
                    font_style: 'Caption'
                    size_hint_y: None
                    height: self.texture_size[1]
                                    
                ScrollView:
                    MDList:
                        OneLineIconListItem:
                            text: 'Room'
                            on_release: root.manager.current = 'room'
                            IconLeftWidget:
                                icon: 'theater'
                                on_release: root.manager.current = 'room'
                                
                        OneLineIconListItem:
                            text: 'Contacts'
                            on_release: root.manager.current = 'contacts'
                            IconLeftWidget:
                                icon: 'contacts'
                                on_release: root.manager.current = 'contacts'
                                
                        OneLineIconListItem:
                            text: 'Calls'
                            on_release: root.manager.current = 'calls'
                            IconLeftWidget:
                                icon: 'cellphone-android'
                                on_release: root.manager.current = 'calls'
                                
                        OneLineIconListItem:
                            text: 'Settings'
                            on_release: root.manager.current = 'settings'
                            IconLeftWidget:
                                icon: 'settings'
                                on_release: root.manager.current = 'settings'
                                
                        OneLineIconListItem:
                            text: 'FAQ'
                            on_release: root.manager.current = 'faq'
                            IconLeftWidget:
                                icon: 'frequently-asked-questions'
                                on_release: root.manager.current = 'faq'
                                
                        OneLineIconListItem:
                            text: 'Invite Friends'
                            on_release: root.manager.current = 'invite'
                            IconLeftWidget:
                                icon: 'account-plus'
                                on_release: root.manager.current = 'invite'
                                
                        OneLineIconListItem:
                            text: 'Theme Manager'
                            on_release:
                                app.change_theme()
                            IconLeftWidget:
                                icon: 'theme-light-dark'

<RoomScreen>:
    name: 'room'
    
    MDLabel:
        text: 'Welcome to the Room Screen'
        halign: 'center'
        bold: True
        font_size: 50
    MDIconButton:
        icon: 'keyboard-backspace'
        pos_hint: {'center_x': 0.06, 'center_y': 0.96}
        on_release: root.manager.current = 'home'
        size_hint: None, None
        
<ContactsScreen>:
    name: 'contacts'
    
    MDLabel:
        text: 'Welcome to the Contacts Screen'
        halign: 'center'
        bold: True
        font_size: 50
    MDIconButton:
        icon: 'keyboard-backspace'
        pos_hint: {'center_x': 0.06, 'center_y': 0.96}
        on_release: root.manager.current = 'home'
        size_hint: None, None
        
<CallsScreen>:
    name: 'calls'
    
    MDLabel:
        text: 'Welcome to the Calls Screen'
        halign: 'center'
        bold: True
        font_size: 50
    MDIconButton:
        icon: 'keyboard-backspace'
        pos_hint: {'center_x': 0.06, 'center_y': 0.96}
        on_release: root.manager.current = 'home'
        size_hint: None, None
        
<SettingsScreen>:
    name: 'settings'
    
    MDLabel:
        text: 'Welcome to the Settings Screen'
        halign: 'center'
        bold: True
        font_size: 50
    MDIconButton:
        icon: 'keyboard-backspace'
        pos_hint: {'center_x': 0.06, 'center_y': 0.96}
        on_release: root.manager.current = 'home'
        size_hint: None, None
        
<FaqScreen>:
    name: 'faq'
    
    MDLabel:
        text: 'Welcome to the Faq Screen'
        halign: 'center'
        bold: True
        font_size: 50
    MDIconButton:
        icon: 'keyboard-backspace'
        pos_hint: {'center_x': 0.06, 'center_y': 0.96}
        on_release: root.manager.current = 'home'
        size_hint: None, None
        
<InviteScreen>:
    name: 'invite'
    
    MDLabel:
        text: 'Welcome to the Invite Screen'
        halign: 'center'
        bold: True
        font_size: 50
    MDIconButton:
        icon: 'keyboard-backspace'
        pos_hint: {'center_x': 0.06, 'center_y': 0.96}
        on_release: root.manager.current = 'home'
        size_hint: None, None
        
<AccountScreen>:
    name: 'account'
    
    BoxLayout:
    
    MDLabel:
        text: 'Account Login'
        pos_hint: {'center_x': 0.6, 'center_y': 0.9}
        color: (1, 1, 1, 1)
        font_size: 40
            
    MDTextFieldRound: 
        id: email
        hint_text: 'Email Address'
        icon_right: 'email'
        icon_right_color: app.theme_cls.primary_color
        pos_hint: {'center_x': 0.5, 'center_y': 0.7}
        size_hint_x: None
        width: 300
    
    MDTextFieldRound: 
        id: password
        hint_text: 'Enter Password'
        icon_right: 'lock'
        icon_right_color: app.theme_cls.primary_color
        password: True
        pos_hint: {'center_x': 0.5, 'center_y': 0.5}
        size_hint_x: None
        width: 300
        
    MDRaisedButton:
        text: 'Login'
        md_bg_color: app.theme_cls.primary_color
        pos_hint: {'center_x': 0.5, 'center_y': 0.2}
        on_release: app.login()       # root.manager.current = 'home'
        
<Friend1>
    name: 'friend1'
    
    BoxLayout:
        orientation: 'vertical'
        
        MDToolbar:
            title: 'Friend 1'
            left_action_items: [['keyboard-backspace', app.change]]
            right_action_items: [['phone', lambda x: print('go ahead and make a call')], ['video', lambda x: print('Video')], ['dots-vertical', lambda x: print('dots')]]

        MDLabel:
            text: 'This is a test screen for our Chat'
            halign: 'center'
        
'''

请伙计们，我真的很感激你的帮助。 提前致谢...

Answer 1

email id仅出现在AccountScreen的ids中。 出现在kv中的任何id都会插入到小部件的ids中，该小部件是包含id的规则的根。 因此，您必须访问AccountScreen实例才能访问email id ：

# BUILDER FUNCTION AND SCREEN
def build(self):
    screen = Screen()

    # theme settings
    self.theme_cls.primary_palette = 'DeepPurple'
    self.theme_cls.theme_style = 'Dark'
    # end of theme declaration

    # loaded strings
    self.navigation_bar = Builder.load_string(toolbar)  # save a reference to the loaded ScreenManager
    # end of loaded strings

    # addition of loaded strings to screen + return screen
    screen.add_widget(self.navigation_bar)

    return screen
    # end of addition

# END OF BUILDER FUNCTION

# USER VALIDATION FUNCTION

def login(self):
    # use the saved reference to access the email address
    email_addr = self.navigation_bar.get_screen('account').ids.email.text

    if email_addr == str(''):
        print('Invalid Email Address')

# END OF USER VALIDATION

Answer 2

value = self.root.get_screen('nameofscreen').ids.username.text
print("What you typed is: ", value)
syntax = self.root.get_screen('name').ids.id.text