Change button Color in Kivy

A Button’s color in Kivy is controlled by the background_color property (an RGBA tuple with values from 0 to 1). This article shows examples that demonstrate how to set a button color and change it at runtime.

This example creates a minimal app with a single red button.

from kivy.app import App
from kivy.uix.button import Button

class BasicColorApp(App):
    def build(self):
        b = Button(text='Red', background_normal='', background_color=(1,0,0,1))
        return b

if __name__ == '__main__':
    BasicColorApp().run()

Output

Explanation:

• App: base class for Kivy applications; build(): returns the root widget shown on screen.
• Button(...): creates a button widget. text: sets the label.
• background_color=(r,g,b,a): RGBA tuple (range 0–1) that tints the button background.
• background_normal: disables the default background image so background_color produces a flat color.

Syntax

Button( text='OK', background_normal='', background_color=(r,g,b,a), color=(r,g,b,a), size_hint=(None,None), size=(w,h), on_press=callback, on_release=callback )

Parameters:

• text: text to display
• background_color: RGBA color for the button (0–1).
• background_normal: set to '' to use a flat color instead of the default image.
• color: RGBA color of the button text.
• size_hint/size: manual sizing when size_hint is (None,None).
• on_press/on_release: events you can bind to functions.

Examples

Example 1: This code shows two side-by-side buttons with different flat colors.

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button

class TwoColorsApp(App):
    def build(self):
        r = BoxLayout(orientation='horizontal', spacing=10, padding=10)
        r.add_widget(Button(text='Blue', background_normal='', background_color=(0,0.7,1,1)))
        r.add_widget(Button(text='Green', background_normal='', background_color=(0,0.8,0.3,1)))
        return r

if __name__ == '__main__':
    TwoColorsApp().run()

Output

Explanation:

• BoxLayout(orientation='horizontal'): arranges children horizontally.
• add_widget(): adds each button to the layout.
• Each Button(...) uses background_normal='' so background_color renders as a flat color.
• spacing and padding control spacing around/between buttons.

Example 2: This code assigns a random flat color to the button each time it is released.

from kivy.app import App
from kivy.uix.button import Button
import random

class RandomColorApp(App):
    def build(self):
        b = Button(text='Random', background_normal='', background_color=(0.5,0.5,0.5,1))
        def on_release(inst):
            inst.background_color = (random.random(), random.random(), random.random(), 1)
        b.bind(on_release=on_release)
        return b

if __name__ == '__main__':
    RandomColorApp().run()

Output

Explanation:

• random.random(): returns a float in [0.0, 1.0], suitable for RGBA components.
• bind(on_release=on_release): triggers after the user lifts the finger/mouse; good for finalizing the action.
• Setting inst.background_color updates the displayed color immediately.