Kivy is a platform-independent GUI tool in Python. How can it run on Android, IOS, Linux and Windows etc. It’s basically used to develop the Android application, but that doesn’t mean it can’t be used in Desktop applications.
In this tutorial we’ll look at how we can use multiple .kv files in a single application. This is the Python program, which uses GridLayout as its root widget. In addition to the main kv file, it loads box1.kv, box2.kv and box3.kv. There are also 2 application variables. These variables are referenced in the main kv file.
Basic Approach: 1) import kivy 2) import kivyApp 3) import Gridlayout 4) import Builder 5) Set minimum version(optional) 6) Create Layout class 7) Create App class 8) Set up multiple .kv file 9) return Layout/widget/Class(according to requirement) 10) Run an instance of the class
.py implementation file:
# Multiple .kv file Python code import kivy # base Class of your App inherits from the App class. # app:always refers to the instance of your application from kivy.app import App # The GridLayout arranges children in a matrix. # It takes the available space and divides # it into columns and rows, then adds # widgets to the resulting “cells”. from kivy.uix.gridlayout import GridLayout # Builder is a global Kivy instance used # in widgets that you can use to load other # kv files in addition to the default ones. from kivy.lang import Builder # Loading Multiple .kv files Builder.load_file(’box1.kv’) Builder.load_file(’box2.kv’) Builder.load_file(’box3.kv’) # Creating main kv file class class main_kv(GridLayout): pass # Create App class class MainApp(App): def build(self): self.x = 150 self.y = 400 return main_kv() # run the App if __name__==’__main__’: MainApp().run()
The main kv file contains a GridLayout with 3 columns. These 3 Columns contains different AnchorLayouts. These all are defined in the main.kv file.
main.kv
# Creating the main .kv files # the difference is that it is # the heart of the Application # Other are just Organs: # Assigning Grids cols: 3 # Creating AnchorLayout AnchorLayout: anchor_x: ’left’ anchor_y: ’center’ # Canvas creation canvas: Color: rgb: [1, 0, 0] Rectangle: pos: self.pos size: self.size Box1: size_hint: [None, None] size: [app.x, app.y] AnchorLayout: anchor_x: ’center’ anchor_y: ’center’ canvas: Color: rgb: [0, 1, 0] Rectangle: pos: self.pos size: self.size Box2: size_hint: [None, None] size: [app.x, app.y] AnchorLayout: anchor_x: ’right’ anchor_y: ’center’ canvas: Color: rgb: [0, 0, 1] Rectangle: pos: self.pos size: self.size Box3: size_hint: [None, None] size: [app.x, app.y]
Now as shown in the Outputs there are different buttons in each grid to create Buttons in every grid we are using Different .kv files.
box1.kv file
# Creating 1st .kv file: Button: text: ’B1a’ Button: text: ’B1b’
box2.kv file
# Creating 2nd .kv file: Button: text: ’B2a’ Button:
box3.kv file
# Creating 3rd .kv file: Button: text: ’B3a’ Button: text: ’B3b’
Is it possible to read from more than one .kv file in Kivy app?
Question from StackOverFlow
I realize the short answer may be ’no,’ but perhaps this is worth asking again.
If I am witting a Kivy app with a couple thousand of lines - then would it be possible to write some classes in another kv file?
This would make it so much easier to edit, correct errors, make changes... etc.
Just to clarify - the .KV files would be a continuation of each other - not pointing to a parallel app.
Some expert insight would be greatly appreciated - Thank you.
Answer
Yes it is! You can import .kv
files inside files just like normal python files by starting with:
#:include otherfile.kv
If you want the file to unload and reload first you can force the import typing
#:include force otherfile.kv
instead.
All this as written in the Kivy Language Documentation which is full of useful clarifications.
Archived version
In this article, we will see how we can use multiple GridLayout as the root widget. In addition to the main kv file, box1.kv
, box2.kv
and box3.kv
are loaded. There are also 2 application variables. These variables are referenced from the main kv file.
Basic Approach: 1) import kivy 2) import kivyApp 3) import Gridlayout 4) import Builder 5) Set minimum version (optional) 6) Create Layout class 7) Create App class 8) Set up multiple .kv file 9) return Layout / widget / Class (according to requirement) 10) Run an instance of the class
main .py implementation file:
|
The main kv file contains a GridLayout with 3 columns ... These 3 columns contain different AnchorLayouts. They are all defined in the main.kv file .
Now the main .kv file:
|
Now, as shown in the Outputs, each grid has different buttons to create buttons.
in each grid we use different .kv files.
file box1.kv —
|
file box2.kv —
|
file box3 .kv —
|
Output: