有人能告诉我这个结构哪里出了问题吗？

Question

我试图从我的.kv调用一个函数，但是我找不到正确的方法来引用绘制小部件的函数之外的函数。我试过了根.dostuff起源。。。自我。。。我的应用程序。。。应用程序。。。我可以把这个函数放到Widgets类中，但这会破坏其他东西。。。你知道吗

你知道吗我的应用程序.py你知道吗

class Widgets(Widget):
    pass

def dostuff(x):
    print(x)

class MyApp(App):
    def build(self):
        global w
        print("Build")
        w = Widgets()
        return w

if __name__ == "__main__":
    MyApp().run()

你知道吗百万千瓦地址：

Button:
    text: "Press Me"
    on_press: dostuff(1)

Answer 1

the correct way to reference a function outside the function that draws the widgets.

您还可以define on_press() outside the kv file：

from kivy.uix.button import Button
from kivy.app import App

def dostuff(x):
    print("x is %s" % x)


class MyButton(Button):
    def on_press(self):
        dostuff(22)

class MyApp(App):

    def build(self):
        return MyButton()

MyApp().run()

你知道吗my.kv地址：

<MyButton>:
    text: "Press Me"

或者，用on_press() inside the kv file：

你知道吗my.kv地址：

<MyButton>:
    text: "Press Me"
    on_press: self.dostuff(10, 20)  #Look in MyButton class for dostuff()

---

...
...

class MyButton(Button):
    def dostuff(self, *args):
        print(args)

...
...

I've tried root.dostuff parent... self... MyApp... App.

以下是root和app在kv文件中的工作方式：

你知道吗my.kv地址：

<MyWidget>: #This class is the 'root' of the following widget hierarchy:
    Button:
        text: "Press Me"
        on_press: root.dostuff(20, 'hello') #Look in the MyWidget class for dostuff()
        size: root.size  #fill MyWidget with the Button

---

from kivy.uix.widget import Widget
from kivy.app import App

class MyWidget(Widget):
    def dostuff(self, *args):
        print(args)

class MyApp(App):

    def build(self):
        return MyWidget()

MyApp().run()

或者，您可以put the function inside the App class：

你知道吗my.kv地址：

<MyButton>:
    text: "Press Me"
    on_press: app.dostuff('hello', 22)

---

from kivy.app import App
from kivy.uix.button import Button

class MyButton(Button):
    pass

class MyApp(App):
    def dostuff(self, *args):
        print(args)

    def build(self):
        return MyButton()

MyApp().run()

I could put the function into the Widgets class, but that breaks other stuff...

好吧，别让函数那样做。你知道吗