How to import kv file from different directory

[GJG]

This question is so basic I was afraid to ask it. I've read through the docs but I can't get imports to work correctly or at all for that matter. I've got a directory structure like so:

src/
├── __init__.py
├── main.kv
├── main.py

└── ui
    ├── __init__.py
    └── other_widgets.kv

Where I want to import widgets defined in ui/other_widgets.kv into main.kv. I keep getting a "kivy.factory.FactoryException: Unknown class <OtherWidget>" error. Below is my code:

main.py

from kivy.app import App
from kivy.lang import Builder


class MainApp(App):
    def build(self):
        Builder.load_file("ui/other_widgets.kv")
        return Builder.load_file("main.kv")


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

main.kv

#:kivy 2.0.0
#:include ui/other_widgets.kv
FloatLayout:
    canvas:
        Color:
            rgb: 0, 1, 0
        Rectangle:
            pos: self.pos
            size: self.size

    OtherWidget:
        size_hint: 0.5, 0.5

other_widgets.kv

#:kivy 2.0.0
<OtherWidget>:
    canvas:
        Color:
            rgb: 0, 0, 1
        Rectangle:
            pos: self.pos
            size: self.size

    Label:
        text: "Other Widget"
What am I doing wrong?

[Elliot Garbus]

There are a few things going on here.

In other_widgets.kv, other_widgets is not inheriting from a widget base class so it is not defined.  Change to:

 

#:kivy 2.0.0
<OtherWidget@BoxLayout>:
    canvas:
        Color:
            rgb: 0, 0, 1
        Rectangle:
            pos: self.pos
            size: self.size

    Label:
        text: "Other Widget"

 

The you can decide either you include it in another file or you do a builder.load_file()

If you do builder.load_file, it must be done prior to build:

 

from kivy.app import App
from kivy.lang import 

Builder

Builder.load_file('ui/other_widgets.kv')  #loading file prior to build

class MainApp(App):
    def build(self):
        return Builder.load_file("main.kv")

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

 

and remove the include in main.kv:

 

#:kivy 2.0.0

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[morsatici]

Thanks Elliot, this answers the question I originally asked but the same problem arises when I add properties in python:

other_widgets.py

from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
from kivy.properties import StringProperty

Builder.load_file("other_widgets.kv")


class OtherWidget(BoxLayout):
    other_property = StringProperty("foobar")

other_widgets.kv

#:kivy 2.0.0
<OtherWidget>:  # I'm assuming kv lang knows OtherWidget is a BoxLayout from other_widgets.py?

    canvas:
        Color:
            rgb: 0, 0, 1
        Rectangle:
            pos: self.pos
            size: self.size

main.py

from kivy.app import App
from kivy.lang import Builder

Builder.load_file("ui/other_widgets.kv")

class MainApp(App):
    def build(self):
        return Builder.load_file("main.kv")


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

main.kv

#:kivy 2.0.0
FloatLayout:
    canvas:
        Color:

            rgb: .9, .9, .9

        Rectangle:
            pos: self.pos
            size: self.size

    OtherWidget:

        id: other_widget

    Label:
        text: other_widget.some_property

I sure it's something simple again, but I can't figure it out.

[Elliot Garbus]

In this case you would import the otherwidgets.py file into main. 

from kivy.app import App
from kivy.lang import Builder

import ui.other_widgets

# Builder.load_file('ui/other_widgets.kv')

class MainApp(App):
    def build(self):
        return Builder.load_file("main.kv")


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

 

In the the other_widgets.py file, the ‘trick’ is the need to specify the ui directory in the load_file call.  This code is being executed in the location it is being imported (main.py)

 

 

from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
from kivy.properties import 

StringProperty

Builder.load_file("ui/other_widgets.kv")

class OtherWidget(BoxLayout):
    other_property = StringProperty("foobar")

In these cases I often like to combine the python and kv code into one file.  This removes the path dependency of the load_file call.

from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
from kivy.properties import 

StringProperty

Builder.load_string("""

<OtherWidget@BoxLayout>:
    canvas:
        Color:
            rgb: 0, 0, 1
        Rectangle:
            pos: self.pos
            size: self.size

    Label:
        text: "Other Widget"

""")

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