Python | Slider widget in Kivy
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
The Slider widget looks like same we are using in android to increase the brightness, volume etc. It supports horizontal and vertical orientations, min/max values and a default value. Kivy supports several slider widget options for customizing the cursor, cursor image, border, background to be used in different orientations, region between the minimum value and the maximum value.
Kivy also supports to deal in term of Normalized value (range 0 to 1) rather than the real ranges supported by the slider.
Basic Approach to follow while creating Slider :
1) import kivy
2) import kivy App
3) import gridlayout(not compulsory according to need)
4) import Label(not compulsory according to need)
5) import Slider
6) import Numeric property
7) set minimum version(optional)
8) Extend the class
9) Add and return a widget
10) Run an instance of the class
Below is the code implementing slider:
Python3
# import kivy module import kivy # this restrict the kivy version i.e # below this kivy version you cannot # use the app or software kivy.require( "1.9.1" ) # Kivy Example App for the slider widget from kivy.app import App # The GridLayout arranges children in a matrix. from kivy.uix.gridlayout import GridLayout # If we will not import this module # It will through the error from kivy.uix.slider import Slider # The Label widget is for rendering text. from kivy.uix.label import Label # Property that represents a numeric value # within a minimum bound and / or maximum # bound – within a numeric range. from kivy.properties import NumericProperty # class in which we are defining the # sliders and its effects class WidgetContainer(GridLayout): def __init__( self , * * kwargs): # super function can be used to gain access # to inherited methods from a parent or sibling # class that has been overwritten in a class object. super (WidgetContainer, self ).__init__( * * kwargs) # 4 columns in grid layout self .cols = 4 # declaring the slider and adding some effects to it self .brightnessControl = Slider( min = 0 , max = 100 ) # 1st row - one label, one slider self .add_widget(Label(text = 'brightness' )) self .add_widget( self .brightnessControl) # 2nd row - one label for caption, # one label for slider value self .add_widget(Label(text = 'Slider Value' )) self .brightnessValue = Label(text = '0' ) self .add_widget( self .brightnessValue) # On the slider object Attach a callback # for the attribute named value self .brightnessControl.bind(value = self .on_value) # Adding functionality behind the slider # i.e when pressed increase the value def on_value( self , instance, brightness): self .brightnessValue.text = "% d" % brightness # The app class class SliderExample(App): def build( self ): widgetContainer = WidgetContainer() return widgetContainer # creating the object root for ButtonApp() class root = SliderExample() # run function runs the whole program # i.e run() method which calls the # target function passed to the constructor. root.run() |
Output:
To add some styling and coloring to the slider, just replace the line no 42 with the below and add some new features also if you want. For text, styling uses the proper commands in text portion.
Python3
# declaring the slider and adding some effects to it # By default its orientation is horizontal # if want to change to vertical do like below self .brightnessControl = Slider( min = 0 , max = 100 , orientation = 'vertical' , value_track = True , value_track_color = [ 1 , 0 , 0 , 1 ]) |
Output:
Video to explain how slider works –
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