How to change text of a label in the kivy language with python
I was wondering how I could change the text of a label made inside the Kivy language using Python. Like how would I have user input from python be made as the text of a label in kivy. (By the way I have the formatting correct in the actual program but I screwed up pasting it to stackoverflow) Say if I wanted to make the text of the label in from the code be a random number generated in python how would I go about doing that?
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.graphics import Color, Rectangle
from kivy.properties import ObjectProperty
# Create both screens. Please note the root.manager.current: this is how
# you can control the ScreenManager from kv. Each screen has by default a
# property manager that gives you the instance of the ScreenManager used.
Builder.load_string("""
<ButImage@ButtonBehavior+AsyncImage>
<TutImage@ButtonBehavior+AsyncImage>
<MenuScreen>:
GridLayout:
cols: 4
row_force_default: True
col_default_width: 175
row_default_height: 150
padding: 15
spacing: 15
canvas.before:
BorderImage:
# BorderImage behaves like the CSS BorderImage
border: 10, 10, 10, 10
source: '/Users/clayhigh/Desktop/kivy/aot.png'
pos: self.pos
size: self.size
Button:
text: 'Goto settings'
background_color: 1,0,0,0.5
on_press: root.manager.current = 'settings'
ButImage:
on_press: root.manager.current = 'UBW'
id: but
size_hint: .5, .5
opacity: 1 if self.state == 'normal' else .5
allow_stretch: True
keep_ratio: False
source: 'http://s3.amazonaws.com/rapgenius/1361742626_beautiful-ocean-beautiful-pictures-27115524-1440-900.jpg'
Label:
center: but.center
text: "UBW"
color: 0.78,0.145,0.016,2
ButImage:
id: lh
size_hint: .5, .5
opacity: 1 if self.state == 'normal' else .5
allow_stretch: True
keep_ratio: False
source: 'http://s3.amazonaws.com/rapgenius/1361742626_beautiful-ocean-beautiful-pictures-27115524-1440-900.jpg'
Label:
center: lh.center
text: "LH 2"
color: 0,0,0,1
ButImage:
id: ttl
size_hint: .5, .5
opacity: 1 if self.state == 'normal' else .5
allow_stretch: True
keep_ratio: False
source: 'http://s3.amazonaws.com/rapgenius/1361742626_beautiful-ocean-beautiful-pictures-27115524-1440-900.jpg'
Label:
center: ttl.center
text: "TwTl"
color: 0,0,0,1
ButImage:
id: gris
size_hint: .5, .5
opacity: 1 if self.state == 'normal' else .5
allow_stretch: True
keep_ratio: False
source: 'http://s3.amazonaws.com/rapgenius/1361742626_beautiful-ocean-beautiful-pictures-27115524-1440-900.jpg'
Label:
center: gris.center
text: "Gris"
color: 0,0,0,1
ButImage:
id: shig
size_hint: .5, .5
opacity: 1 if self.state == 'normal' else .5
allow_stretch: True
keep_ratio: False
source: 'http://s3.amazonaws.com/rapgenius/1361742626_beautiful-ocean-beautiful-pictures-27115524-1440-900.jpg'
Label:
center: shig.center
text: "Shig"
color: 0,0,0,1
Button:
text: 'Test3'
background_color: 1,0,0,0.5
Button:
text: 'Test4'
background_color: 1,0,0,0.5
Button:
text: 'Quit'
background_color: 1,0,0,0.5
on_press: App.on_stop
<SettingsScreen>:
GridLayout:
row_force_default: True
row_default_height: 100
cols: 2
canvas.before:
BorderImage:
# BorderImage behaves like the CSS BorderImage
border: 10, 10, 10, 10
source: '/Users/clayhigh/Desktop/kivy/ato.jpeg'
pos: self.pos
size: self.size
Button:
text: 'Button'
color: 0,0,.5
background_color: 1,0,0,1
Button:
text: 'Back to menu'
background_color: 1,0,0,1
on_press: root.manager.current = 'menu'
<UBW>:
GridLayout:
row_force_default: True
row_default_height: 100
cols: 2
canvas.before:
Color:
rgb: .5, .5, .5
Rectangle:
pos: self.pos
size: self.size
Color:
rgb: 1, 1, 1
BorderImage:
# BorderImage behaves like the CSS BorderImage
border: 10, 10, 10, 10
source: '/Users/clayhigh/Desktop/kivy/fsn.jpg'
pos: self.pos
size: self.size
Button:
text: 'Back to menu'
color: 0,0,.5
on_press: root.manager.current = 'menu'
background_color: 1,0,0,1
Label:
id: AName
text: "F S/N: UBW"
font_size: '24sp'
""")
# Declare both screens
class MenuScreen(Screen):
pass
class SettingsScreen(Screen):
pass
class UBW(Screen):
pass
# Create the screen manager
sm = ScreenManager()
sm.add_widget(MenuScreen(name='menu'))
sm.add_widget(SettingsScreen(name='settings'))
sm.add_widget(UBW(name='UBW'))
class TestApp(App):
def build(self):
return sm
if __name__ == '__main__':
TestApp().run()
Answer
Text of a label can be a kivy property, which can be later changed and since it is a kivy property it will automatically updated everywhere. Here is an example of your .py
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.properties import StringProperty
import random
class YourWidget(Widget):
random_number = StringProperty()
def __init__(self, **kwargs):
super(YourWidget, self).__init__(**kwargs)
self.random_number = str(random.randint(1, 100))
def change_text(self):
self.random_number = str(random.randint(1, 100))
class YourApp(App):
def build(self):
return YourWidget()
if __name__ == '__main__':
YourApp().run()
and your .kv
<YourWidget>:
BoxLayout:
size: root.size
Button:
id: button1
text: "Change text"
on_release: root.change_text()
Label:
id: label1
text: root.random_number
When you click the button, it will call change_text() function, which will randomly change the text of the label to random integer between 1 and 100.