將 ScreenManager 與每個屏幕的單獨 py 和 kv 文件一起使用

Question

我正在制作一個計算器應用程序，我希望能夠為每個屏幕使用單獨的 kv 和 py 文件，我沒有找到任何關於此的文檔或教程，我找到的唯一答案沒有給出代碼示例所以我不確定如何實現它。 此外，calc.kv 上的按鈕通過在 root 中引用它來向 calc.py 發送回調，這樣可能會導致問題，因為 root 是 screenmanager

如果您嘗試從工具欄中打開計算器，它將返回此錯誤消息：

 screen = self.get_screen(value)
   File "C:\Python38\lib\site-packages\kivy\uix\screenmanager.py", line 1071, in get_screen
     raise ScreenManagerException('No Screen with name "%s".' % name)
 kivy.uix.screenmanager.ScreenManagerException: No Screen with name "calc".

這是代碼：

計算.py

from logging import root
from kivymd.app import MDApp
from kivy.uix.widget import Widget
from kivy.core.window import Window
from kivy.properties import StringProperty
from kivy.lang import Builder


prev = ""
expression = "" 
prox = "" 
class calc(Widget):
    pass
    out = StringProperty('')
    Window.size = (420, 200)
    Window.minimum_width, Window.minimum_height = Window.size
    
    
    
    def my_callback(self, inpt):
        global prev
        global expression
        global prox
        
            
        if inpt == "=":
            prox = str(eval(expression))
            self.out = prox
            expression = ""
            prev = prox
            
            
        elif inpt == "ac":
            expression = ""
            prev = ""
            prox = ""
            self.out = expression
        
        
            
        else:
            expression = prev + inpt
            prev = expression
            self.out = expression
        
         
        
                    
class calcApp(MDApp):  
    def build(self):
        def press(text):
            print("called: ", text)
    
        return calc()


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

計算.kv

#:kivy 1.0.9

   

<calc>:
    BoxLayout:
        orientation: 'vertical'
        
        cols: 2
        size: root.width, root.height

        MDLabel:
            id: 'output'
            text: str(root.out)
            size_hint: 1, 0.2
            halign: 'center'

        GridLayout:
                       
            cols: 5
            MDFlatButton:
                
                text: '1'
                on_press: root.my_callback(self.text)
                
            MDFlatButton:
                
                text: '2' 
                on_press: root.my_callback(self.text)
            
            MDFlatButton:
                
                text: '3'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '-'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                text: 'ac'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '4'  
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '5' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '6'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '+' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                text: '('
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '7' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '8' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '9' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '*'
                on_press: root.my_callback(self.text)
            
            MDFlatButton:
                text: ')'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '0' 
                on_press: root.my_callback(self.text)
            MDFlatButton:
                
                text: '.'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                text: '/'
                on_press: root.my_callback(self.text)

            
            MDFlatButton:
                
                text: '**'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '='
                on_press: root.my_callback(self.text)            
            

主文件

#:kivy 1.0.9

#: include calc.kv

NavigationLayout:
    id: nav_layout

    ScreenManager:

        Screen:

            BoxLayout:
                orientation: 'vertical'

                MDToolbar:
                    title: app.title
                    elevation: 10
                    left_action_items: [['menu', lambda x: nav_drawer.set_state()]]

                ScreenManager:
                    id: screen_manager
                    calculator:
                        
                    

    MDNavigationDrawer:
        id: nav_drawer

        BoxLayout:
            orientation: 'vertical'
            padding: '8dp'
            spacing: '8dp'

            Image:
                size_hint: None, None
                size: '280dp', "200dp"
                source: "logo.png"
            
            ScrollView:
            
                MDList:

                    OneLineIconListItem:
                        text: "calculadora"
                        on_release:
                            screen_manager.current = 'calc'
                            nav_drawer.set_state()
                        IconLeftWidget:
                            icon: 'view-dashboard'

主文件

import calc
from kivymd.app import MDApp
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager

class ScreenManager(ScreenManager):
    pass

class MyApp(MDApp):
    def build(self):
        self.title = "calculadora"
        self.theme_cls.primary_palette = "Green"
        return Builder.load_file("main.kv")


MyApp().run()

提前致謝。

Answer 1

您需要為 calc.kv 文件中的<calc>命名，而不是從Widget class 繼承，而是從 calc.py 文件中的Screen class 繼承。 之后，您需要使用Builder.load_file("calc.kv")在 your.kv 中添加calc() Screen ，如on_release

calc.py （只需在此處將 inheritance 從Widget更改為Screen ）

from logging import root
from kivymd.app import MDApp
from kivy.uix.screenmanager import Screen
from kivy.core.window import Window
from kivy.properties import StringProperty
from kivy.lang import Builder


prev = ""
expression = "" 
prox = "" 
class calc(Screen):
    out = StringProperty('')
    Window.size = (420, 200)
    Window.minimum_width, Window.minimum_height = Window.size
    
    
    
    def my_callback(self, inpt):
        global prev
        global expression
        global prox
        
            
        if inpt == "=":
            prox = str(eval(expression))
            self.out = prox
            expression = ""
            prev = prox
            
            
        elif inpt == "ac":
            expression = ""
            prev = ""
            prox = ""
            self.out = expression
        
        
            
        else:
            expression = prev + inpt
            prev = expression
            self.out = expression
        
         
        
                    
class calcApp(MDApp):  
    def build(self):
        def press(text):
            print("called: ", text)
    
        return calc()


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

calc.kv （只需給 class 起一個名稱以供參考）

#:kivy 1.0.9

   

<calc>:
    name: 'calc'
    BoxLayout:
        orientation: 'vertical'
        
        cols: 2
        size: root.width, root.height

        MDLabel:
            id: 'output'
            text: str(root.out)
            size_hint: 1, 0.2
            halign: 'center'

        GridLayout:
                       
            cols: 5
            MDFlatButton:
                
                text: '1'
                on_press: root.my_callback(self.text)
                
            MDFlatButton:
                
                text: '2' 
                on_press: root.my_callback(self.text)
            
            MDFlatButton:
                
                text: '3'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '-'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                text: 'ac'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '4'  
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '5' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '6'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '+' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                text: '('
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '7' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '8' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '9' 
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '*'
                on_press: root.my_callback(self.text)
            
            MDFlatButton:
                text: ')'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '0' 
                on_press: root.my_callback(self.text)
            MDFlatButton:
                
                text: '.'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                text: '/'
                on_press: root.my_callback(self.text)

            
            MDFlatButton:
                
                text: '**'
                on_press: root.my_callback(self.text)

            MDFlatButton:
                
                text: '='
                on_press: root.my_callback(self.text)

main.py （只需在開始時加載 calc.kv）

import calc
from kivymd.app import MDApp
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager

Builder.load_file("calc.kv")

class MyApp(MDApp):
    def build(self):
        self.title = "calculadora"
        self.theme_cls.primary_palette = "Green"
        return Builder.load_file("main.kv")


MyApp().run()

main.kv （只需導入 calc class，並將其 object 添加到管理器中）

#:kivy 1.0.9
#:import calc calc.calc

NavigationLayout:
    id: nav_layout

    ScreenManager:

        Screen:

            BoxLayout:
                orientation: 'vertical'

                MDToolbar:
                    title: app.title
                    elevation: 10
                    left_action_items: [['menu', lambda x: nav_drawer.set_state()]]

                ScreenManager:
                    id: screen_manager
                    calculator:
                        
                    

    MDNavigationDrawer:
        id: nav_drawer

        BoxLayout:
            orientation: 'vertical'
            padding: '8dp'
            spacing: '8dp'

            Image:
                size_hint: None, None
                size: '280dp', "200dp"
                source: "logo.png"
            
            ScrollView:
            
                MDList:

                    OneLineIconListItem:
                        text: "calculadora"
                        on_release:
                            screen_manager.add_widget(calc())
                            screen_manager.current = 'calc'
                            nav_drawer.set_state()
                        IconLeftWidget:
                            icon: 'view-dashboard'