CODEWITHSUNDEEP
pythonbuttonkivy
Xonu
Xonu

Reputation: 671

Background Button Color Doesn't Change on_press

I am trying to make this simple script change a button's color when pressed with the on_press behavior.

Python Script: kivytest.py 

#Import Libraries

#Import Kivy GUI
import kivy

#From kivy, import base class App
# app: always refers to instance of this application
from kivy.app import App

from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.stacklayout import StackLayout

################################################################################
# Creating the root widget used in the .kv file
class testLayout(StackLayout):
    pass

################################################################################

class kivytestApp(App):

    def build(self):
        return testLayout()

test = kivytestApp()

test.run()

Corresponding .kv file: kivytest.kv 

<StackLayout>:

    #Create the canvas
    canvas:
        #Color the canvas background a dark gray with alpha = 1
        Color:
            rgba: 0.11, 0.15, 0.17, 1

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

    #Provide the orientation of the stack layout from left to right / top to bottom
    orientation: "lr-tb"

    #Add padding between children and layout
    padding: 10

    #Add spacing between each of its children
    spacing: 5

    Button:
        size_hint: 0.2, None
        text: "second button"
        background_color: [1, 0, 0, 1]
        background_normal: ''
        on_press:
            background_color: [0, 1, 0, 1]
            print("second button pressed")

Unfortunately when I press the button in the app, the color remains red, but slightly darker red on_press, instead of green which I have specified. What should I correct? Is this implementation not as simple as it seems?

Upvotes: 2

Views: 261

Answers (1)

eyllanesc
eyllanesc

Reputation: 244311

You have 2 errors:

  • By just indicating background_color you are creating a variable other than the background_color property of the Button. To refer to the same object that has the scope you must use self.

  • You should not use : in the assignment within an event but = (I think it's a bug that kivy doesn't throw an error in this case)

Considering the above, the solution is:

on_press:
    self.background_color = [0, 1, 0, 1]
    print("second button pressed")

Upvotes: 3

Related Questions