Error: First letter of class name <classname> is in lowercase

[Hepha1st0s]

Hi everyone, 

I have started working with Kivy and have encountered the following problem:

No matter what I do, I always get the following error:

 
AttributeError: First letter of class name <<Menu>> is in lowercase

The code in the files looks like this:

MyApp.py:

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

class Menu(Widget):
    pass

class MyApp(App):
    def build(self):
        return Menu()
   
if __name__ == "__main__":
    MyApp().run()

---------------------------------------------------------------------------------

my.kv:

<menu>:
    Label:
        text: "Hello World"

I have tried all possible upper-lower case variations but nothing works. Can someone please help me?

[Elliot Garbus]

<Menu>:
    Label:
        text: "Hello World"

The kv code in the <> needs to match the name of the python class definition.

 

As an aside, there is no reason in this case to put a label inside a Widget, a Label is derived frow a Widget.  Put widgets in Layouts.  The layouts position and size their child widgets.

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[Hepha1st0s]

Thank you for your reply. Unfortunately, I accidentally copied the wrong code into the my.kv file. The actual code is:

<Menu>
    text: "Hello World

So the name inside the <> and the class name matches, otherwise the case would be clear. I am a bit at a loss here :( 

[Elliot Garbus]

Try this:

 

from kivy.app import App
from kivy.uix.label import Label


class Menu(Label):
    pass


class MyApp(App):
    def build(self):
        return Menu()

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

 

my.kv:

<Menu>
    text: "Hello World"

To view this discussion on the web visit https://groups.google.com/d/msgid/kivy-users/7ada8272-c13d-446a-bc93-a9a89137e23bn%40googlegroups.com.

 

[Hepha1st0s]

I got the same error again. I even followed the tutorial on the kivy.org website (that pong game) and also got the stupid error.

[Elliot Garbus]

Do you have only one kv file in the directory?  The code I posted runs for me.

To view this discussion on the web visit https://groups.google.com/d/msgid/kivy-users/a008e3e8-4538-4cbf-ad9c-5d277fcd1536n%40googlegroups.com.

 

[Hepha1st0s]

I have the solution. Apparently I am not allowed to create a KV file using VSC :D 

If I first create a .txt file and rename it, it works beautifully!

Now I'm relieved, thanks for your help!