在kivy中使用python將變量從一個屏幕更改爲其他屏幕

我有兩個屏幕kivy應用程序，我想使用python將變量從一個屏幕傳遞到第二個屏幕。在kivy中使用python將變量從一個屏幕更改爲其他屏幕

Python文件

from kivy.app import App 
from kivy.uix.boxlayout import BoxLayout 
from kivy.uix.screenmanager import ScreenManager, Screen 
from kivy.properties import StringProperty,ObjectProperty 
from kivy.uix.label import Label 

class MenuScreen(Screen): 
    label1=StringProperty() 
    label2=StringProperty() 
    def __init__(self,**kwargs): 
     super(MenuScreen, self).__init__(**kwargs) 
     self.label1="hello" 
     self.label2="world" 
    def change_text(self):   
     lbl1=self.label1+ " and " 
     lbl2= "A beautiful "+self.label2 
     chg=SettingsScreen() 
     chg.UpdateSettings(lbl1,lbl2) 

     # HERE: something like 



class SettingsScreen(Screen): 
    label3=StringProperty() 
    label4=StringProperty() 
    def __init__(self,**kwargs): 
     super(SettingsScreen, self).__init__(**kwargs) 
     #some default texts 
     self.label3="Nothing" 
     self.label4="Nothing" 
    def UpdateSettings(self,lbl1,lbl2): 
     print(lbl1,lbl2) 
     self.label3=lbl1 
     self.label4=lbl2 

class TestScreenManager(ScreenManager): 
    menu_screen=ObjectProperty(None) 
    settings_screen=ObjectProperty(None) 

class TestApp(App): 
    def build(self):    
     return TestScreenManager() 

TestApp().run()

kvfile

#: import ScreenManager kivy.uix.screenmanager.ScreenManager 
#: import Screen kivy.uix.screenmanager.ScreenManager 
#: import SettingsScreen screen 


<TestScreenManager>: 
    id: screen_manager 
    menu_screen: menu_screen 
    settings_screen: settings_screen 

    MenuScreen: 
     id: menu_screen 
     name: 'menu' 
     manager: screen_manager 
    SettingsScreen: 
     id: settings_screen 
     name: 'settings_screen' 
     manager: screen_manager 


<MenuScreen>: 
    name: 'MenuScreen' 
    BoxLayout: 
     Label: 
      text:root.label1 
     Label: 
      text:root.label2 
     Button: 
      text: 'Goto nn' 
      size_hint_y:0.2 
      on_press: 
       root.manager.current = 'settings_screen' 
       root.change_text() 


<SettingsScreen>: 
    #name: 'SettingsScreen' 
    label_id: label_field 
    BoxLayout: 
     Label: 
      text:root.label3 
     Label: 
      text:root.label4 
     Label: 
      id: label_field 
      text: "some text"

它運行沒有錯誤，但它不改變第二屏幕的變量。爲了調試，我在UpdateSetting函數中添加了print(lbl1,lbl2)，並打印出傳遞lbl1和lbl2變量，但不更新標籤。

來源

2017-07-20 Eka

當您執行chg=SettingsScreen()時，您正在創建SettingsScreen類的新實例，並且您修改了該實例的標籤。您需要訪問ScreenManager使用的對象，而不是創建一個新對象。

您可以使用當前屏幕的manager屬性來獲取其他屏幕的實例的引用：

def change_text(self):   
    lbl1=self.label1 + " and " 
    lbl2= "A beautiful "+ self.label2 
    chg = self.manager.settings_screen #<<<<<<<<<<<<<< 
    chg.UpdateSettings(lbl1,lbl2)

來源

2017-07-20 04:12:31 FJSevilla

在kivy中使用python將變量從一個屏幕更改爲其他屏幕

回答

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