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What is the purpose of the `self` parameter? Why is it needed?
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Closed 3 years ago.
I would like to change a Label-text in Python/Kivy after a swipe event has been detected. Changing the text works basically via the following line
self.Translation.text = "test"
but I have to change the text after detecting a swipe event from another class, in which I call a function to change the label text:
MyWidget.ThisDoesntWork("self_dummy")
In this function the exact same line as above gives me an error.
How can I change the Label-text from class "Swiping_class" calling function "MyWidget.ThisDoesntWork("self_dummy")"?
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.textinput import TextInput
from kivy.base import EventLoop
from kivy.clock import Clock
from kivy.factory import Factory
from kivy.uix.stacklayout import StackLayout
from kivy.uix.image import Image
from kivy.uix.floatlayout import FloatLayout
from kivy.graphics import *
from kivy.properties import ListProperty
from kivy.lang import Builder
from kivy.core.window import Window
from kivy.uix.screenmanager import ScreenManager, Screen
from random import random
import pickle
import random
kv = '''
<ColoredLabel>:
size: (self.size_x,self.size_y)
pos: (0,0) # no effect
background_color:
canvas.before:
Color:
rgba: self.background_color
Rectangle:
pos: self.pos
size: (self.size_x,self.size_y)
'''
Builder.load_string(kv)
class ColoredLabel(Label):
background_color = ListProperty((0,0,0,1))
s_global = Window.size
size_x = s_global[0]
size_y = s_global[1]/3
class MyWidget(BoxLayout):
#init
def __init__(self, **kwargs):
super().__init__(**kwargs)
s_global = Window.size
size_x = s_global[0]
size_y = s_global[1]/3
self.ForeignLanguage = ColoredLabel(text="str_fl", size_hint=(None, None),size = (size_x,size_y), background_color=(0/255,171/255,169/255, 1))
self.Translation = ColoredLabel(text="str_tr", size_hint=(None, None),size = (size_x,size_y), background_color=(45/255,137/255,239/255, 1))
self.Example = ColoredLabel(text="str_ex", size_hint=(None, None),size = (size_x,size_y), background_color=(43/255,87/255,151/255, 1))
self.verticalBox = BoxLayout(orientation='vertical')
self.verticalBox.add_widget(self.ForeignLanguage)
self.verticalBox.add_widget(self.Translation)
self.verticalBox.add_widget(self.Example)
self.Translation.text = "test"
s=Swiping_class()
s.add_widget(self.verticalBox)
self.add_widget(s)
def ThisDoesntWork(self):
print("this is printed")
self.Translation.text = "I wanna change this via fucntion"
print("this is not printed anymore")
class Swiping_class(Screen):
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.initial = 0
def on_touch_down(self, touch):
self.initial = touch.x
def on_touch_up(self, touch):
if touch.x < self.initial:
print("swiped left")
MyWidget.ThisDoesntWork("self_dummy")
else:
print("swiped right")
class BoxLayoutDemo(App):
def build(self):
return MyWidget()
if __name__ == '__main__':
BoxLayoutDemo().run()
I think I found a solution. Within your Swiping_class, replace this line:
MyWidget.ThisDoesntWork("self_dummy")
with this line:
MyWidget.ThisDoesntWork(self.parent)
That way, instead of passing a string to your method, you pass the label object, which contains the text attribute you are trying to modify.
Related
I want to create a list of coloured labels. The thing is that I could do it with the kv file, but I need to do it through the build() method. So I tried replicate what I have done, but it does not work. And I can't understand why.
This is what I've coded
from kivy.app import App
from kivy.uix.relativelayout import RelativeLayout
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.graphics import *
class RL(RelativeLayout): # Creates the background colour for each label
def __init__(self, **kwargs):
super().__init__(**kwargs)
with self.canvas:
Color(.7, 0, .5, 1)
Rectangle(size_hint=self.size)
class MainMenu(BoxLayout):
N_LBLS = 8
labels_text = []
RL_list = []
def __init__(self, **kwargs):
super().__init__(**kwargs)
button = Button(text='do something')
button.bind(on_release=self.change_text)
box = BoxLayout(orientation='vertical', padding= 10, spacing = 15)
for i in range(0, self.N_LBLS):
self.RL_list.append(RL())
self.labels_text.append(Label(text=f'{i}º label', size_hint=self.size))
self.RL_list[i].add_widget(self.labels_text[i])
box.add_widget(self.RL_list[i])
self.add_widget(button)
self.add_widget(box)
def change_text(self, instance):
for lbl in self.labels_text:
if lbl.text[0] == '5':
lbl.text = 'Text changed'
class MainApp(App):
def build(self):
return MainMenu()
if __name__ == '__main__':
MainApp().run()
It's supposed to make a button to the left, and a list of 8 coloured labels to the right.
The problem is that you are setting size_hint=self.size in each Label. The self.size is the size of the MainMenu, which is [100,100] when that code is executed. Note that size_hint is a multiplier that is applied to the parents size to calculate the widgets size. So a size_hint of [100,100] makes each Label 100 times bigger than the MainMenu. So your code is working, but the Labels are so large that the text is off the screen. Start by just removing size_hint=self.size.
And, to set a background color on a Label, you can just use the canvas of that Label, rather than some container. Here is a version of your code that does that:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.button import Button
from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
class ColorLabel(Label):
pass
Builder.load_string('''
<ColorLabel>:
bg_color: [.7, 0, .5, 1]
canvas.before:
Color:
rgba: self.bg_color
Rectangle:
pos: self.pos
size: self.size
''')
class MainMenu(BoxLayout):
N_LBLS = 8
labels_text = []
def __init__(self, **kwargs):
super().__init__(**kwargs)
button = Button(text='do something')
button.bind(on_release=self.change_text)
box = BoxLayout(orientation='vertical', padding=10, spacing=15)
for i in range(0, self.N_LBLS):
self.labels_text.append(ColorLabel(text=f'{i}º label'))
box.add_widget(self.labels_text[i])
self.add_widget(button)
self.add_widget(box)
def change_text(self, instance):
for lbl in self.labels_text:
if lbl.text[0] == '5':
lbl.text = 'Text changed'
lbl.bg_color = [0, 1, 0, 1]
class MainApp(App):
def build(self):
return MainMenu()
if __name__ == '__main__':
MainApp().run()
from kivy.uix.button import Button
from kivy.uix.behaviors.button import ButtonBehavior
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.image import Image
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.clock import Clock
from kivy.uix.widget import Widget
from kivy.graphics import BorderImage
from kivy.graphics import Color, RoundedRectangle, Rectangle, Triangle
from kivy.core.window import Window
#from kivy.config import Config
from kivy.uix.checkbox import CheckBox
from kivy.uix.popup import Popup
from kivy.uix.scrollview import ScrollView
from kivy.uix.filechooser import FileChooserListView
from kivy.properties import ObjectProperty
class OpeningPage(FloatLayout):
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.but = RoButton(text = 'START', pos = (350,100), font_size=14, size=(100,60), size_hint=(None,None))
self.add_widget(self.but)
class RoButton(Button):
butt = ObjectProperty()
def __init__(self, **kwargs):
super(RoButton, self).__init__(**kwargs)
text = self.text
with self.canvas:
# Color(1., 0, 0)
self.butt = RoundedRectangle( size= self.size, pos = self.pos, radius =[400])
class UI(App):
def build(self):
self.screen_manager = ScreenManager()
self.opening_page = OpeningPage()
screen = Screen(name ='Opening_Page')
screen.add_widget(self.opening_page)
self.screen_manager.add_widget(screen)
return self.screen_manager
if __name__ == '__main__':
the_app = UI()
the_app.run()
Everytime I try to make a circular button using this code I get a box behind the circle. I tried doing self.canvas.before but still no luck if possible could answers be in python rather than .kv language thanks.
Attached image of problem]1
The box you see is the normal Button image. If you don't want that, probably don't use a Button, instead use class RoButton(ButtonBehavior, Widget):.
The problem is in the .kv file. My problem is that i would like my .kv to notice the object-property in my .py. My code works if change the color in .kv to color: 0,0,0 which gives me black text as intend.
.py
from kivy import utils
from kivy.animation import Animation
from kivy.clock import Clock
from kivy.properties import ObjectProperty
from kivy.uix.label import Label
from kivy.lang import Builder
from kivy.uix.button import ButtonBehavior
Builder.load_file("FirebaseLoginScreen/themedwidgets.kv")
class ThemedButton(ButtonBehavior,Label):
colorchanged = ObjectProperty()
color = ObjectProperty([0,0,0,1])
def __init__(self, **kwargs):
super(ThemedButton, self).__init__(**kwargs)
Clock.schedule_once(self.start_pulsing, 1)
def start_pulsing(self, *args):
anim = Animation(color=[0,1,0,1]) + Animation(color=[0,0,1,1]) + Animation(color=[1,0,0,1])
anim.repeat = True
anim.start(self)
.kv
<ThemedButton#ButtonBehavior+Label>:
colorchanged: colorchanged
id: colorchanged
markup: True
color: self.color #root.color doesn't work either but 0,0,0 does give me black.
opacity: 1 if self.state == 'normal' else .8
font_size: 38
<ThemedButton#ButtonBehavior+Label>:
This is the kv syntax to create a new widget class inheriting from ButtonBehavior and Label, so it doesn't have any of the behaviour of your Python-defined class that happens to have the same name.
You want to just do <ThemedButton>: instead.
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.core.window import Window
from kivy.uix.scrollview import ScrollView
from kivy.effects.scroll import ScrollEffect
from kivy.uix.widget import Widget
from kivy.uix.button import Button
class BSGameMain:
def sas(self):
# blmain.remove_widget(scrlFBtns)
self.scrlFBtns.remove_widget(blbtns)
blmain = BoxLayout(orientation = 'vertical') # MainBoxLayout init
scrlFBtns = ScrollView(effect_cls = 'ScrollEffect')
blbtns = BoxLayout(
orientation = 'vertical',
size_hint_y = None
) # BoxLayout for buttons
blbtns.bind(minimum_height = blbtns.setter('height'))
scrlFBtns.add_widget(blbtns)
for i in range (2):
blbtns.add_widget(Button(
text='asd',
size_hint_y = None,
height = 40,
on_press = sas
))
lblmain = Label(text = 'asd')
blmain.add_widget(lblmain)
blmain.add_widget(scrlFBtns)
class BSApp(App):
def build(self):
game = BSGameMain()
return game.blmain
if __name__ == "__main__":
BSApp().run()
AttributeError 'Button' object has no attribute scrlFBtn. What is the problem? I'm trying to make it so that when you clicked, the screen was cleared (Widget was deleted). Рelp me please =)
Your code has several errors and bad programming practices:
if you declare variables that are inside a class and outside any method of the class will be class variables and not attributes of the class, so it is not a good practice to do so if you want to use later self, all that code must be within a method of a class.
on_someproperty wait as parameter a function that receives parameters, in your case sas() does not receive them so the solution is to use a lambda method.
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.label import Label
from kivy.uix.scrollview import ScrollView
from kivy.effects.scroll import ScrollEffect
from kivy.uix.button import Button
class BSGameMain:
def __init__(self):
self.blmain = BoxLayout(orientation = 'vertical') # MainBoxLayout init
self.scrlFBtns = ScrollView(effect_cls = 'ScrollEffect')
self.blbtns = BoxLayout(
orientation = 'vertical',
size_hint_y = None )
self.blbtns.bind(minimum_height = self.blbtns.setter('height'))
self.scrlFBtns.add_widget(self.blbtns)
for i in range(2):
self.blbtns.add_widget(Button(
text='asd',
size_hint_y = None,
height = 40,
on_press = lambda *args: self.sas()))
lblmain = Label(text = 'asd')
self.blmain.add_widget(lblmain)
self.blmain.add_widget(self.scrlFBtns)
def sas(self):
self.scrlFBtns.remove_widget(self.blbtns)
class BSApp(App):
def build(self):
game = BSGameMain()
return game.blmain
if __name__ == "__main__":
BSApp().run()
I'm trying to find a solution to embed a graph within a kivy widget. There seems to be only one example of using kivy garden graph (sin wave) and I'm having difficulty implementing this within my app.
Here is the code that I'm working with
#!/usr/bin/kivy
import kivy
from random import random
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.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.uix.switch import Switch
from kivy.uix.label import Label
from kivy.garden.graph import Graph, MeshLinePlot
from math import sin
import matplotlib.pyplot as plt
import matplotlib.animation as animation
from kivy.graphics import *
from kivy.config import Config
Config.set('graphics', 'width', '800')
Config.set('graphics', 'height', '480')
Builder.load_string("""
<Menuscreen>:
#Handling the gesture event.
ScreenManager:
id: manager
Screen:
id: main_screen
name:'main_screen'
FloatLayout:
MyGraph:
size_hint: None, None
size: 800,600
pos: 25,25
""")
class MyGraph(Graph):
def __init__(self, **kwargs):
super(MyGraph, self).__init__(**kwargs)
self.xlabel = 'This is the X axis'
self.ylabel = 'This is the Y axis'
self.x_ticks_minor = 5
self.x_ticks_major = 25
self.y_ticks_major = 1
self.y_grid_label = True
self.x_grid_label = True
self.x_grid = True
self.y_grid = True
self.xmax = 100
self.xmin = -0
self.ymin = -1
self.ymax = 1
self.plot = MeshLinePlot(color=[1, 0, 0, 1])
self.plot.points = [(x, sin(x / 10.)) for x in range(0, 100)]
self.add_plot(self.plot)
class MenuScreen(Screen):
pass
sm = ScreenManager()
menu_screen = MenuScreen(name='menu')
sm.add_widget(menu_screen)
class TestApp(App):
def build(self):
return sm
if __name__ == '__main__':
TestApp().run()
All of the axis labels seem to appear but the points on the graph do not appear. Is there something that I am missing to get this to appear? Thanks in advance for your advice.
Mostafar at Github asked this same question, and thanks to #Tshirtman, the following answer was provided:
mostafar commented on Apr 27, 2014 After a chat with #tshirtman, He found out the problem is with stencilbuffer and by changing line 139 of init.py of graph module to:
self._fbo = Fbo(size=self.size, with_stencilbuffer=False)
It will be visible in my example, but then there will be many problems with new features of graph (SmoothLinePlot).
Link: https://github.com/kivy-garden/garden.graph/issues/7