在 Python 中将值从方法中提取到其他类中

问：

我正在用 Kivy 编写一个 Python 脚本。截至目前，该应用程序按预期工作。除了我遇到了障碍，无法找到解决方案。在“class Output（screen）”类中，我想从“Class Cost（Screen）”和“Class Tip（Screen）”类中提取从屏幕输入生成的值。现在，在编写代码时，来自屏幕的输入被拉入相应的类（Cost 和 Tip）中，并用 Python 打印。所以，我知道这个逻辑是有效的。我需要一种方法在类 Output（Screen） 中调用这些值。提前感谢您的任何建议。

import kivy
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.properties import ObjectProperty




class Cost(Screen):
    cost = ObjectProperty(None)

    def btn(self):
        cost = self.ids.cost.text
        print(cost)


class Tip(Screen):
    tip = ObjectProperty(None)

    def btn(self):
        tip = self.ids.tip.text
        print(tip)


class Output(Screen):
    pass


class WindowManager(ScreenManager):
    pass


kv = Builder.load_file("att.kv")


class ATT(App):
    def build(self):
        return kv





if __name__ == "__main__":
    ATT().run()
type here

att.kv 文件

<Label>:
    color:0.5,0.5,0.5,1
    font_size:30

<Button>:
    background_color: 0, 0, 3, .6
    color:1.0,1.0,1.0,1
    font_size:20
    markup: True

WindowManager
    Cost:
    Tip:
    Output:

<Cost>
    name: "Cost"
    cost: cost

    Label:
        size_hint:{0.3, 0.2}
        pos_hint: {"x":0.20, "y":0.5}
        color:1.0,1.0,1.0,1
        text: "What's the Total Bill? $"

    TextInput:
        focus: "True"
        id: cost
        size_hint:{0.2, 0.1}
        pos_hint: {"x":0.58, "y":0.55}
        multiline:False
        input_filter: "float"

    Button:
        size_hint:{0.2, 0.1}
        pos_hint: {"x":0.4, "y":0.2}
        text: "[b]Next[/b]"
        on_press: root.btn()
        on_release:
            app.root.current = "Tip"
            root.manager.transition.direction = "left"

<Tip>
    name: "Tip"
    tip: tip

    Label:
        size_hint:{0.3, 0.2}
        pos_hint: {"x":0.24, "y":0.5}
        color:1.0,1.0,1.0,1
        text: "Tip Percentage? %"

    TextInput:
        id: tip
        size_hint:{0.2, 0.1}
        pos_hint: {"x":0.58, "y":0.55}
        multiline:False
        input_filter: "float"

    Button:
        size_hint:{0.2, 0.1}
        pos_hint: {"x":0.5, "y":0.2}
        text: "[b]Next[/b]"
        on_press: root.btn()
        on_release:
            app.root.current = "Output"
            root.manager.transition.direction = "left"


    Button:
        size_hint:{0.2, 0.1}
        pos_hint: {"x":0.27, "y":0.2}
        text: "[b]Back[/b]"
        on_release:
            app.root.current = "Cost"
            root.manager.transition.direction = "right"

<Output>
    name: "Output"

    Label:
        size_hint:{0.3, 0.2}
        pos_hint: {"x":0.20, "y":0.5}
        color:1.0,1.0,1.0,1
        text: "Output"


    Button:
        size_hint:{0.2, 0.1}
        pos_hint: {"x":0.5, "y":0.2}
        text: "[b]Close[/b]"
        on_press: app.stop()



    Button:
        size_hint:{0.2, 0.1}
        pos_hint: {"x":0.27, "y":0.2}
        text: "[b]Start Over[/b]"
        on_press:
            app.root.current = "Cost"
            root.manager.transition.direction = "right"