CODEWITHSUNDEEP
kivy
Saurabh Shrivastava
Saurabh Shrivastava

Reputation: 1484

Change button text value for on_press event in Kivy

My application has a single button with text value as '2'. I want to change the text value to 100 on on_press event

My attempt:

#!/usr/bin/kivy
import kivy
kivy.require('1.7.2')

from random import random
from random import choice
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.gridlayout import GridLayout
from kivy.uix.button import Button

r1c2=random()
Builder.load_string("""
<Highest>:
    r1c2: str(2)
    GridLayout:
        cols: 1
        Button:
            text: root.r1c2
            on_press: root.new()
""")

class Highest(Screen):
    def new(self):
        r1c2=str(100)


# Create the screen manager
sm = ScreenManager()
sm.add_widget(Highest(name='Highest'))

class TestApp(App):

    def build(self):
        return sm

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

Error: Currently, nothing happens when the button is pressed. Please help

Upvotes: 1

Views: 1765

Answers (1)

laltin
laltin

Reputation: 1152

You should be using kivy properties available. See kivy.properties for more information.

Add this import for access to string property: 

from kivy.properties import StringProperty

And your Highest class should be:

class Highest(Screen):
    r1c2 = StringProperty(str(2))

    def new(self):
        self.r1c2 = str(100)

At initialization r1c2 value is equal to '2'. When the function new() is called value of r1c2 will become '100'. Button text is bind to the string property r1c2 so it will automatically change.

You don't need r1c2=str(2) in your builder string. 

Builder.load_string("""
<Highest>:
    GridLayout:
        cols: 1
        Button:
            text: root.r1c2
            on_press: root.new()
""")

Upvotes: 1

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