Python | Slider widget using .kv file

Last Updated : 07 Feb, 2020

Kivy is a platform independent GUI tool in Python. As it can be run on Android, IOS, linux and Windows etc. It is basically used to develop the Android application, but it does not mean that it can not be used on Desktops applications.

👉🏽 Kivy Tutorial - Learn Kivy with Examples.

Slider: To work with the slider you first have to import the module which consists all features, functions of the slider i.e.

Module: kivy.uix.slider

Basic Approach to follow while creating Slider -

1) import kivy
2) import kivyApp
3) import BoxLayout
4) set minimum version(optional)
5) Extend the class
6) set up .kv file (name same as the Slider.kv)
7) Run an instance of the class

Below is the code implementing slider with .kv file:

Python3

# main.py file of slider 

# base Class of your App inherits from the App class.  
# app:always refers to the instance of your application  
from kivy.app import App

# BoxLayout arranges children in a vertical or horizontal box. 
# or help to put the children at the desired location. 
from kivy.uix.boxlayout import BoxLayout 


# creating the root widget used in .kv file 
class SliderWidget(BoxLayout):
    pass

# class in which name .kv file must be named Slider.kv.
# or creating the App class
class Slider(App):
    def build(self):
        # returning the instance of SliderWidget class 
        return SliderWidget()

# run the app    
if __name__ == '__main__':
    Slider().run()

Now the .kv file : Slider.kv file

Python3

<SliderWidget>:

    # creating the Slider
    Slider:
        
        # giving the orientation of Slider
        orientation: "vertical"
        min: 0  # minimum value of Slider
        max: 100 # maximum value of Slider
        value: 0  # initial value of Slider

        # when slider moves then to increase value
        on_value:label1.text = str(int(self.value))

    # Adding label
    Label:
        id: label1
        font_size: "30sp"
        text: "0"
        color: 1, 0, 0, 1

    Slider:
        orientation: "horizontal"
        min: 0
        max: 100
        value: 30
        on_value:label2.text = str(int(self.value))
        

    Label:
        id: label2
        font_size: "30sp"
        text: "30"
        color: 0, 0, 1, 1