App.root must be an _instance_ of Widget. Invalid instance in App.root

Question

I'm not exactly new to python but wouldn't I know it well and fully, but I'm completely new to Kivy. It's just a small thing I'm doing just to start somewhere. I'm working in Visual Studio Code(VSC). Python version 3.10. The idea is: there are 5 buttons, each button has a name, when you click on a button, image(meme) should show up. Here is the full code, terminal, debugger and what is in command prompt:

code code

Terminal Terminal

Debugger Debugger

Command Prompt Command Prompt

Here is python itself and a folder "Projects" C:\Users\Кирилл\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Python 3.10 enter image description here

Here is folder with virtual environment(App_EPQ) and a folder with code(App_code) C:\Users\Кирилл\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Python 3.10\Projects enter image description here

Thanks in advance

Tried to rewrite the code but that didn't work. Tried to find someone with a similar problem no luck there also. No idea what to do next and how to fix it so this is my last hope.

Answer 1

Your class has to inherit a layout as well as App:

    class HBoxLayoutExample(BoxLayout, App)

Another way to do it would be to create a class that builds the app and returns the layout:

    class HBoxLayoutExample(BoxLayout)
    **your code**

    class HBoxApp(App):
        def build(self):
            return HBoxLayoutExample
    if __name__ == '__main__':
        HBoxApp().run()

as shown here https://kivy.org/doc/stable/guide/lang.html#designing-with-the-kivy-language

Answer 2

Replace your line:

return layout, button

with:

return layout

That's all. build() method have to return one widget, which in your case is BoxLayout instance.