how to implement a kv file by initializing a class

[Edward Anderson]

I am attempting to divide a large project into individual steps with each step having its own kv file to format that step. The 3 attached files are organized so that MModel.py is the executive program that initializes a class in Directory.py with an attached prbdir,ky file.  Directory.py and prbdir.kv are in a subdirectory of the MModel.py directory. All of these are placed in a single Python package. When I run the Directory.py file, everything executes as intended with a label and title being displayed. When I execute the MModel.py file (Initializing the Directory class) only a blank screen (without label) is displayed. So, my question is how to implement a kv file by initializing a class?

[ElliotG]

You can pull a kv file into a python file a number of ways.
If the kv file has the same name as the app, it will load by default.

You can use Builder.load_file('pdbdir.kv')  to load a kv file explicitly
or use Builder.load_string(kv_string) to load kv.

to use Builder, use

from kivy.lang import Builder

[Edward Anderson]

Hunter: Your description is exactly what I am trying to do.

Eliot: Your suggestion sound like what I need to do to accomplish my objective. I will try it when I get a chance.

Thanks to both of you.

--
You received this message because you are subscribed to the Google Groups "Kivy users support" group.
To unsubscribe from this group and stop receiving emails from it, send an email to kivy-users+...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/kivy-users/c2f87b2c-2079-46fa-aa24-ac674fbd42f1n%40googlegroups.com.

[Edward Anderson]

Another problem. I am attempting to activate a python callback function using MDButton on_press method. My python and kv files are attached. A portion of the error messages I receive are below:  TIA

 kivy.lang.builder.BuilderException: Parser: File "C:\Users\edand\PycharmProjects\MechanicsModel\mdtest.kv", line 23:
 ...
      21:        MDButtonText:
      22:            text: "Submit"
 >>   23:            on_press: app.btnfunc()
 ...
 AttributeError: press
   File "C:\Users\edand\PycharmProjects\MechanicsModel\.venv\Lib\site-packages\kivy\lang\builder.py", line 734, in _apply_rule
     raise AttributeError(key)

[ElliotG]

You can simplify your python code.  Because your kv file name and app class file name are the same the kv file is loaded automatically.

from kivymd.app import MDApp

class MDtest(MDApp):

    def btnfunc(self):
        print("button is pressed!!")


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

In your kv code, the on_press event is an event of MDButton, not MDButtonText, change as below:

    MDButton:
        style: 'elevated'
        pos_hint: {'center_x': 0.5, 'center_y': 0.3}
        on_press: app.btnfunc()  
        MDButtonIcon:
            icon: 'plus'
        MDButtonText:
            text: "Submit"