Python KivyMD - 从一个屏幕输入，在另一个屏幕显示输出

Question

我想制作一个 2 页的 Kivy 应用程序 - 输入一个单词，在另一个屏幕上输出定义。我试过Kivy，它奏效了。现在我使用 KivyMD。我遇到了 NameError。

   Traceback (most recent call last):
   File "C:/Users/Andrew/PycharmProjects/JesscarlettApp/dictapp.py", line 94, in <module>
     TestApp().run()
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivy\app.py", line 950, in run
     runTouchApp()
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivy\base.py", line 582, in runTouchApp
     EventLoop.mainloop()
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivy\base.py", line 347, in mainloop
     self.idle()
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivy\base.py", line 391, in idle
     self.dispatch_input()
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivy\base.py", line 342, in dispatch_input
     post_dispatch_input(*pop(0))
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivy\base.py", line 308, in post_dispatch_input
     wid.dispatch('on_touch_up', me)
   File "kivy\_event.pyx", line 709, in kivy._event.EventDispatcher.dispatch
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivymd\uix\behaviors\ripplebehavior.py", line 245, in on_touch_up
     return super().on_touch_up(touch)
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivymd\uix\button.py", line 969, in on_touch_up
     return super().on_touch_up(touch)
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivy\uix\behaviors\button.py", line 179, in on_touch_up
     self.dispatch('on_release')
   File "kivy\_event.pyx", line 705, in kivy._event.EventDispatcher.dispatch
   File "kivy\_event.pyx", line 1248, in kivy._event.EventObservers.dispatch
   File "kivy\_event.pyx", line 1132, in kivy._event.EventObservers._dispatch
   File "C:\Users\Andrew\PycharmProjects\JesscarlettApp\lib\site-packages\kivy\lang\builder.py", line 57, in custom_callback
     exec(__kvlang__.co_value, idmap)
   File "<string>", line 24, in <module>
 NameError: name 'meaning' is not defined

这是我的 main.py 和 kv。 （请忽略那些额外未使用的模块。） 问题在于 kv 中的这一行“meaning.text = app.show_data_meaning()”。但我只是不知道如何解决它。非常感谢。

from kivy.app import App
from kivymd.uix.screen import Screen
from kivy.uix.screenmanager import ScreenManager, Screen
from kivymd.uix.textfield import MDTextField
from kivy.lang import Builder
from kivy.uix.label import Label
from kivymd.uix.button import MDRectangleFlatButton
from kivy.core.window import Window
from kivy.uix.image import Image, AsyncImage
from kivymd.app import MDApp
from PyDictionary import PyDictionary
from bs4 import BeautifulSoup as bs
from kivymd.uix.label import MDLabel


class WordScreen(Screen):
    pass


class MeaningScreen(Screen):
    pass


screen_helper = """
ScreenManager:
    id: screen_manager
    
    WordScreen:
    MeaningScreen:

<WordScreen>
    name: 'wordscreen'
    MDTextField:
        hint_text: "Word"
        id: text_field
        text:'default'
        icon_right: "dictionary"
        icon_right_color: app.theme_cls.primary_color
        pos_hint: {'center_x':0.5, 'center_y':0.9}
        size_hint_x:None
        width:300
    MDRectangleFlatButton:
        text: 'search'
        id: search_button
        pos_hint: {'center_x': 0.5, 'center_y': 0.8}
        on_release: 
            meaning.text = app.show_data_meaning()
            root.manager.current = 'meaningscreen'
            
<MeaningScreen>
    name: 'meaningscreen'
    MDRectangleFlatButton:
        text: 'back'
        pos_hint: {'center_x': 0.5, 'center_y': 0.2}
        on_release: root.manager.current = 'wordscreen' 
    MDLabel:
        text: "Default"
        id: meaning
        halign: 'center'
        theme_text_color: 'Secondary'
        font_style: 'Body1'
        pos_hint: {'center_x': 0.5, 'center_y': 0.6} 

"""

class TestApp(MDApp):
    def __init__(self, **kwargs):
        self.title = "Dictionary App"
        self.theme_cls.primary_palette = "Blue"
        super().__init__(**kwargs)

    def build(self):
        sm = Builder.load_string(screen_helper)
        return sm

    def show_data_meaning(self):
        searchword = self.root.get_screen("wordscreen").ids.text_field.text
        print(searchword)
        dictionary = PyDictionary(searchword)
        meaning = dictionary.getMeanings()
        print(meaning)
        return meaning


if __name__ == '__main__':
    TestApp().run()

Answer 1

您可以在TestApp 中创建一个新方法来设置下一个屏幕上的文本

示例：

    def my_func(self):
        self.root.get_screen("meaningscreen").ids.meaning.text = str(self.show_data_meaning())

并在按钮释放中调用您的方法

on_release: 
        app.my_func()
        root.manager.current = 'meaningscreen'

您也可以在 kv 文件中执行此操作，您只需要获取含义屏幕 然后meaningscreen.ids.text_field.meaning.text = app.show_data_meaning()

这是您更改后的代码

from kivy.app import App
from kivymd.uix.screen import Screen
from kivy.uix.screenmanager import ScreenManager, Screen
from kivymd.uix.textfield import MDTextField
from kivy.lang import Builder
from kivy.uix.label import Label
from kivymd.uix.button import MDRectangleFlatButton
from kivy.core.window import Window
from kivy.uix.image import Image, AsyncImage
from kivymd.app import MDApp
from PyDictionary import PyDictionary
from bs4 import BeautifulSoup as bs
from kivymd.uix.label import MDLabel


class WordScreen(Screen):
    pass


class MeaningScreen(Screen):
    pass


screen_helper = """
ScreenManager:
    id: screen_manager

    WordScreen:
    MeaningScreen:

<WordScreen>
    name: 'wordscreen'
    MDTextField:
        hint_text: "Word"
        id: text_field
        text:'default'
        icon_right: "dictionary"
        icon_right_color: app.theme_cls.primary_color
        pos_hint: {'center_x':0.5, 'center_y':0.9}
        size_hint_x:None
        width:300
    MDRectangleFlatButton:
        text: 'search'
        id: search_button
        pos_hint: {'center_x': 0.5, 'center_y': 0.8}
        on_release: 
            app.my_func()
            root.manager.current = 'meaningscreen'

<MeaningScreen>
    name: 'meaningscreen'
    MDRectangleFlatButton:
        text: 'back'
        pos_hint: {'center_x': 0.5, 'center_y': 0.2}
        on_release: root.manager.current = 'wordscreen' 
    MDLabel:
        text: "Default"
        id: meaning
        halign: 'center'
        theme_text_color: 'Secondary'
        font_style: 'Body1'
        pos_hint: {'center_x': 0.5, 'center_y': 0.6} 

"""


class TestApp(MDApp):
    def __init__(self, **kwargs):
        self.title = "Dictionary App"
        self.theme_cls.primary_palette = "Blue"
        super().__init__(**kwargs)

    def build(self):
        sm = Builder.load_string(screen_helper)
        return sm

    def show_data_meaning(self):
        searchword = self.root.get_screen("wordscreen").ids.text_field.text
        print(searchword)
        dictionary = PyDictionary(searchword)
        meaning = dictionary.getMeanings()
        print(meaning)
        return meaning

    def my_func(self):
        self.root.get_screen("meaningscreen").ids.meaning.text = str(self.show_data_meaning())


if __name__ == '__main__':
    TestApp().run()