I understand that it is relatively easy to switch screens in the .kv file using on_release. I want to keep my button creating in the .py file, however, so I do not want to use this method. I have done the following to add a function that occurs when the 14th button is pressed. When the button is pressed in the program nothing happens. Experimenting with other names for the screen to sm.current to threw the error: "kivy.uix.screenmanager.ScreenManagerException: No Screen with name "InputScreen" when the 14th button was pressed."
# Kivy Formatting
kv_text='''\
<MyScreenManager>:
LandingScreen:
InputScreen:
<InputScreen#Screen>:
name: 'input_sc'
AnchorLayout:
id: anchor_1
<LandingScreen#Screen>:
name: 'landing_sc'
GridLayout:
id: grid_1
cols: 5
height: 480
width: 800
spacing: 25, 20
padding: 25,25
'''
# Screen Manager
class MyScreenManager(ScreenManager):
pass
# Main screen with button layout
class LandingScreen(Screen):
def __init__(self, **kwargs):
super(LandingScreen, self).__init__(**kwargs)
self.buttons = [] # add references to all buttons here
Clock.schedule_once(self._finish_init)
# IDs have to be used here because they cannot be applied until widget initialized
def _finish_init(self, dt):
self.ids.grid_1.cols = 5
# Loop to make 15 different buttons on screen
for x in range(15):
self.buttons.append(Button(text='button {}'.format(x)))
self.ids.grid_1.add_widget(self.buttons[x])
self.buttons[x].background_normal = 'YOUTUBE.png'
def SwitchScreen(self,*args):
sm.current = 'input_sc'
sm = ScreenManager()
sm.add_widget(InputScreen(name='input_sc'))
sm.add_widget(LandingScreen(name='landing'))
self.buttons[14].bind(on_release=SwitchScreen)
# Input screen
class InputScreen(Screen):
pass
class MySubApp(App):
def build(self):
return MyScreenManager()
def main():
Builder.load_string(kv_text)
app = MySubApp()
app.run()
if __name__ == '__main__':
main()
If someone could help me understand the hole in my current logic I would appreciate it greatly. Thanks.
Each screen has a manager property that gives you the instance of the ScreenManager used. You only need to use it to refer to the ScreemManager instance and use its current method:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.button import Button
from kivy.clock import Clock
# Kivy Formatting
kv_text='''\
<MyScreenManager>:
LandingScreen:
InputScreen:
<InputScreen#Screen>:
name: 'input_sc'
AnchorLayout:
id: anchor_1
Button:
text: 'Hello'
<LandingScreen#Screen>:
name: 'landing_sc'
GridLayout:
id: grid_1
cols: 5
height: 480
width: 800
spacing: 25, 20
padding: 25,25
'''
# Screen Manager
class MyScreenManager(ScreenManager):
pass
# Main screen with button layout
class LandingScreen(Screen):
def __init__(self, **kwargs):
super(LandingScreen, self).__init__(**kwargs)
self.buttons = [] # add references to all buttons here
Clock.schedule_once(self._finish_init)
# IDs have to be used here because they cannot be applied until widget initialized
def _finish_init(self, dt):
self.ids.grid_1.cols = 5
# Loop to make 15 different buttons on screen
for x in range(15):
self.buttons.append(Button(text='button {}'.format(x)))
self.ids.grid_1.add_widget(self.buttons[x])
self.buttons[x].background_normal = 'YOUTUBE.png'
self.buttons[14].bind(on_release=self.switch_screen)
def switch_screen(self, *args):
self.manager.current = 'input_sc'
# Input screen
class InputScreen(Screen):
pass
class MySubApp(App):
def build(self):
return MyScreenManager()
def main():
Builder.load_string(kv_text)
app = MySubApp()
app.run()
if __name__ == '__main__':
main()
Related
I'm making an App in kivy, and I want to be able to drag a widget anywhere in my "tacscreen" how can I do that? I have a GridLayout with an Image in my "tacscreen". Below is my code! I already looked at the documents still couldn't find a solution. Any help is appreciated! Thank You!
main.py
from kivy.app import App
from kivy.uix.screenmanager import Screen
from kivy.clock import Clock
from functools import partial
class StartScreen(Screen):
pass
class TacScreen(Screen):
pass
class MainApp(App):
def on_start(self):
Clock.schedule_once(partial(self.change_screen, "tac_screen"), 5)
def change_screen(self, screen_name, *args):
self.root.current = screen_name
MainApp().run()
tacscreen.kv
#:import utils kivy.utils
<TacScreen>:
canvas.before:
Rectangle:
pos: self.pos
size: self.size
source: "Game.png"
GridLayout:
rows: 1
pos: 0, 102
size_hint: 1, .1
Image:
source: "Pencil.png"
In the official Kivy documentation there is an example that you may find helpful.
I'm not familiar with the .kv file so I use kivy.lang.Builder.load_string instead
and one small thing is that seems like the build function which helps build the GUI part is missing ( maybe ) just added
my solution is :
when pointer is touch inside the widget ( by binding on_touch_move as follow ) , the position of the center of the widget ( you can also change it by <widget_instance>.<x / right / y / top / etc> = value ) will be the position of the pointer touch
when releases , the widget will also adjust itself too : ) from the funciton on_touch_up
so the full code will be as follow :
import kivy
from kivy.app import App
from kivy.uix.screenmanager import Screen, ScreenManager # added ScreenManager
from kivy.clock import Clock
# from functools import partial
kivy.lang.Builder.load_string("""
#:kivy 2.0.0
#:import utils kivy.utils
<StartScreen>: # added
Label:
text: "Hello World !"
font_size: 25
size: self.texture_size
<TacScreen>:
# I skipped the canvas , add it back later lol : )
GridLayout:
id: mygridlayout # add an id to the widget ( a name which represent the widget )
rows: 1
pos: 0, 102
size_hint: 1, .1
Button: # widget
text: "HI !"
# skipped the Image part
""")
class StartScreen(Screen):
pass
class TacScreen(Screen):
def on_touch_up(self, touch):
# to prevent it dragging from out the screen
if (self.ids.mygridlayout.x < 0) or (
self.ids.mygridlayout.right > self.right):
self.ids.mygridlayout.x = 0
if self.ids.mygridlayout.top > self.top:
self.ids.mygridlayout.top = self.top
if self.ids.mygridlayout.y < 0:
self.ids.mygridlayout.y = 0
def on_touch_move(self, touch): # bind when pointer touch + move on screen
# use self.ids.<widget_id> to get the instance of widget
if (self.ids.mygridlayout.x < touch.x < self.ids.mygridlayout.right) and (
self.ids.mygridlayout.top > touch.y > self.ids.mygridlayout.y):
self.ids.mygridlayout.center = (touch.x, touch.y)
class MainApp(App):
screen_manager = ScreenManager()
def on_start(self):
Clock.schedule_once(lambda dt: self.change_screen("tac_screen"), 5)
def change_screen(self, screen_name: str, *args):
# self.root.current = screen_name
self.screen_manager.current = screen_name
def build(self): # we use this method build to return stuff to the GUI window ( maybe )
# add screens to screen manager
self.screen_manager.add_widget(StartScreen(name = "start_screen"))
self.screen_manager.add_widget(TacScreen(name = "tac_screen"))
# screen manager transition direction
self.screen_manager.transition.direction = "up" # left, right, up, down
self.on_start() # maybe you want to call it here ?
return self.screen_manager
MainApp().run()
any suggestions / improvement etc. is welcome : )
In my Kivy-App, i generate Buttons via a python-class based on a dictionary (in the following example i use a list but that's just an example for the underlying problem).
Within the App, the dictionary gets changed and i want to display that change (obviously) in my App (by adding/ removing/ rearranging the Buttons).
To achieve this, my approach is to either restart the entire App or only reload that particular BoxLayout. Unfortunately, non of my attempts worked out so far and i could not find any (working) solution on the internet.
This is my code example:
Python Code:
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
buttonlist = []
counter = 0
class MainWindow(BoxLayout):
def addbutton(self):
global buttonlist
global counter
buttonlist.append(counter)
counter += 1
class ButtonBox(BoxLayout):
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.orientation = "vertical"
global buttonlist
for button in buttonlist:
b = Button(text=str(button))
self.add_widget(b)
class KivyApp(App):
def build(self):
return MainWindow()
KivyApp().run()
KV Code:
<MainWindow>:
BoxLayout:
ButtonBox:
Button:
text: "add Button"
on_press: root.addbutton()
My closest attempt was something containing a restart-Method like:
def restart(self):
self.stop()
return KivyApp().run()
and calling:
App.get_running_app().restart()
But for some reason, this does not stop the App but opens a second instance of the App within the first one (resulting in App in App in App in App if pressed often)
You can rebuild the ButtonBox by first calling clear_widgets() on the ButtonBox instance. Here is a modified version of your code that does that:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
kv = '''
<MainWindow>:
BoxLayout:
ButtonBox:
id: box
Button:
text: "add Button"
on_press: root.addbutton()
'''
buttonlist = ['Abba', 'Dabba', 'Doo']
counter = 3
class MainWindow(BoxLayout):
def addbutton(self):
global buttonlist
global counter
buttonlist.append(str(counter))
counter += 1
self.ids.box.reload()
class ButtonBox(BoxLayout):
def __init__(self, **kwargs):
super().__init__(**kwargs)
self.orientation = "vertical"
self.reload()
def reload(self):
# method to rebuild the ButtonBox contents
global buttonlist
self.clear_widgets()
for button in buttonlist:
b = Button(text=str(button))
self.add_widget(b)
class KivyApp(App):
def build(self):
Builder.load_string(kv)
return MainWindow()
KivyApp().run()
I used your kv as a string, just for my own convenience.
I would like to populate MyData with information gathered from dropdown menus that show up in a popup window with "on_touch_up" in AddTouch. That data includes the position of "on_touch_up", in addition to the dropdown data. I am able to print the position within the AddTouch class, but I am having a hard time getting the data further down in my script using (for example: print('from MyMainApp: {}'.format(MyData.pos))).
I am also unable to get "mainbutton" or "dropdown" to show up in a popup window.
Hacking around with this I came up with the following which works, but doesn't do what i need
.py
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.lang import Builder
from kivy.uix.dropdown import DropDown
from kivy.uix.popup import Popup
from kivy.uix.button import Button
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.graphics import Color, Rectangle
class AddTouch(Widget):
def __init__(self, **kwargs):
super(AddTouch, self).__init__(**kwargs)
with self.canvas:
Color(1, 0, 0, 0.5, mode="rgba")
self.rect = Rectangle(pos=(0, 0), size=(10, 10))
def on_touch_down(self, touch):
self.rect.pos = touch.pos
def on_touch_move(self, touch):
self.rect.pos = touch.pos
def on_touch_up(self, touch):
# final position
self.pos = touch.pos
print(self.pos)
class MyPopup(Popup):
def __init__(self, **kwargs):
super(MyPopup, self).__init__(**kwargs)
# create a main button
self.mainbutton = Button(text='Hello', size_hint=(None, None))
# create a dropdown with 10 buttons
self.dropdown = DropDown()
for index in range(10):
btn = Button(text='Value %d' % index, size_hint_y=None, height=44)
btn.bind(on_release=lambda btn: self.dropdown.select(btn.text))
self.dropdown.add_widget(btn)
self.mainbutton.bind(on_release=self.dropdown.open)
self.dropdown.bind(on_select=lambda instance, x: setattr(self.mainbutton, 'text', x))
class MyData:
def __init__(self, **kwargs):
super(MyData, self).__init__(**kwargs)
self.pos=AddTouch.pos
# using kivy screen for consistency
class MainWindow(Screen):
pass
class WindowManager(ScreenManager):
pass
kv = Builder.load_file("dropd.kv")
class MyMainApp(App):
def build(self):
return kv
print('from MyMainApp: {}'.format(MyData.pos))
if __name__ == "__main__":
MyMainApp().run()
.kv
WindowManager:
MainWindow:
<MainWindow>:
name: "main"
AddTouch:
on_touch_up:
#MyPopup gives 'MyPopup' is not defined, even if I add <MyPopup>: below
#root.MyPopup gives 'MainWindow' object has no attribute 'MyPopup'
I tried adding a simple dynamic Popup class in the .kv file based on this, but again it says 'MyPopup' is not defined:
.kv
AddTouch
on_touch_up:
MyPopup
<MyPopup#Popup>:
auto_dismiss: False
Button:
text: 'Close me!'
on_release: root.dismiss()
What am I missing (other than experience, ability, and general intelligence)?
In addition to adding the line:
self.content = self.mainbutton
to the MyPopup __init__() method, you can trigger the MyPopup creation by modifying your .kv file as:
#:import Factory kivy.factory.Factory
WindowManager:
MainWindow:
<MainWindow>:
name: "main"
AddTouch:
on_touch_up:
Factory.MyPopup().open()
New to kivy, and OOP.
I'm trying to update a label in kivy with data I pull from a temp sensor. The code that pulls in the sensor data is in labeltempmod. I created a function getTheTemp() that is called every second. In the function I try to assign the text of the label via Label(text=(format(thetemp)), font_size=80). The program ignores this. What am I doing wrong here?
#This is a test to see if I can write the temp to label
import labeltempmod
import kivy
from kivy.app import App
from kivy.clock import Clock
from kivy.uix.label import Label
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.textinput import TextInput
from kivy.uix.boxlayout import BoxLayout
def getTheTemp(dt):
thetemp = labeltempmod.readtemp()
Label(text=(format(thetemp)), font_size=80)
print thetemp
class LabelWidget(BoxLayout):
pass
class labeltestApp(App):
def build(self):
# call get_temp 0.5 seconds
Clock.schedule_interval(getTheTemp, 1)
return LabelWidget()
if __name__ == "__main__":
labeltestApp().run()
Here is the kivy language file:
<LabelWidget>:
orientation: 'vertical'
TextInput:
id: my_textinput
font_size: 80
size_hint_y: None
height: 100
text: 'default'
FloatLayout:
Label:
id: TempLabel
font_size: 150
text: 'Temp Test'
Thanks.
Sorry but you never update something You are just creating another label
Try this:
class LabelWidget(BoxLayout):
def __init__(self, **kwargs):
super(LabelWidget, self).__init__(**kwargs)
Clock.schedule_interval(self.getTheTemp, 1)
def getTheTemp(self, dt):
thetemp = labeltempmod.readtemp()
self.ids.TempLabel.text = thetemp
print thetemp
class labeltestApp(App):
def build(self):
return LabelWidget()
if __name__ == "__main__":
labeltestApp().run()
Update : for your last request, I think the best way to do that is:
...
class LabelWidget(BoxLayout):
def __init__(self, **kwargs):
super(LabelWidget, self).__init__(**kwargs)
self.Thetemp = None
Clock.schedule_interval(self.getTheTemp, 1)
def getTheTemp(self, dt):
if self.Thetemp is None:
self.thetemp = labeltempmod.readtemp()
else:
self.thetemp = labeltempmod.readtemp(self.theTemp)
self.ids.TempLabel.text = str(self.thetemp)
I want to access root widgets ids from other rootwidgets, but I can't seem to fully grasp how referencing works in Kivy and using a ScreenManager with different screens makes it even harder for me.
I want to achieve the following:
Edit: single file version
(This code assumes you're going to build a complex app, so I don't want to load all code at startup. Hence the kv_strings are loaded when switching screen, and not put into kv code of the ScreenManager. Code is based on the Kivy Showcase.)
Code main.py, Edit 2: working code (see answer why)
#!/usr/bin/kivy
# -*- coding: utf-8 -*-
from kivy.app import App
from kivy.uix.screenmanager import Screen
from kivy.uix.boxlayout import BoxLayout
from kivy.lang import Builder
from kivy.clock import Clock
from kivy.properties import StringProperty, ObjectProperty
kv_foo = '''
<FooScreen>:
id: fooscreen_id
BoxLayout:
id: content
orientation: 'vertical'
spacing: '20dp'
padding: '8dp'
size_hint: (1, 1)
BoxLayout:
orientation: 'vertical'
Label:
id: important_text
size_hint_y: 0.3
text: app.imp_text
Button:
id: magic_change
size_hint_y: 0.3
text: "Change text above to text below (after screen switch)"
on_press: app.change_text()
ScreenManager:
id: sm
on_current_screen:
idx = app.screen_names.index(args[1].name)
'''
class FooScreen(Screen):
# 'content' refers to the id of the BoxLayout in FooScreen in foo.kv
def add_widget(self, *args):
if 'content' in self.ids:
return self.ids.content.add_widget(*args)
return super(FooScreen, self).add_widget(*args)
class FooApp(App):
imp_text = StringProperty("Should change to text from id: magic_text")
screen_magic = ObjectProperty()
magic_layout = ObjectProperty()
def build(self):
self.title = 'Foo'
self.root = root = Builder.load_string(kv_foo)
# Trying stuff with References
self.sm = self.root.ids.sm # ScreenManager
# Setting up screens for screen manager
self.screens = {}
self.available_screens = [kv_mainmenu, kv_magic]
self.screen_names = ['MainMenu', 'Magic']
self.go_screen(0)
# Go to other screen
def go_screen(self, idx):
print("Change MainScreen to: {}".format(idx))
self.index = idx
# Go to not main menu
if idx == 0:
self.root.ids.sm.switch_to(self.load_screen(idx), direction='right')
# Go to main menu
else:
self.root.ids.sm.switch_to(self.load_screen(idx), direction='left')
# Load kv files
def load_screen(self, index):
if index in self.screens:
return self.screens[index]
screen = Builder.load_string(self.available_screens[index])
self.screens[index] = screen
# if index refers to 'Magic' (kv_magic), create reference
if index == 1:
Clock.schedule_once(lambda dt: self.create_reference())
return screen
# Trying to get id's
def create_reference(self):
print("\nrefs:")
# Get screen from ScreenManager
self.screen_magic = self.sm.get_screen(self.screen_names[1])
# screen.boxlayout.magiclayout
self.magic_layout = self.screen_magic.children[0].children[0]
def change_text(self):
# Get text from id: magic_text
if self.magic_layout:
self.imp_text = self.magic_layout.ids['magic_text'].text
kv_mainmenu = '''
FooScreen:
id: mainm
name: 'MainMenu'
Button:
text: 'Magic'
on_release: app.go_screen(1)
'''
kv_magic = '''
<MagicLayout>
id: magic_layout
orientation: 'vertical'
Label:
id: magic_text
text: root.m_text
FooScreen:
id: magic_screen
name: 'Magic'
MagicLayout:
id: testmagic
'''
class MagicLayout(BoxLayout):
m_text = StringProperty("Reference between widgets test")
if __name__ == '__main__':
FooApp().run()
Question
How can I set up proper references that the button "Change text above..." can retrieve magic_text.text ("Reference between widgets test") and change self.imp_text to magic_text.text?
I found a way to reference to Kivy widgets not loaded at the startup of the app without using globals. Thanks #inclement for ScreenManager.get_screen().
I had to add the following code:
class FooApp(App):
screen_magic = ObjectProperty()
magic_layout = ObjectProperty()
...
# Trying to get id's
def create_reference(self):
print("\nrefs:")
# Get screen from ScreenManager
self.screen_magic = self.sm.get_screen(self.screen_names[1])
# screen.boxlayout.magiclayout
self.magic_layout = self.screen_magic.children[0].children[0]
def change_text(self):
# Get text from id: magic_text
if self.magic_layout:
self.imp_text = self.magic_layout.ids['magic_text'].text
self.screen_magic is assigned the screen I need (<FooScreen>) and self.magic_layout is assigned the widget I need (<MagicLayout>). Then I can use the ids from <MagicLayout> to access the Label magic_text's text.
(For full code see updated question)