I'd like to have a kivy app function as a launcher for other kivy apps, depending on input. The way I implemented it below is obviously not working (because the kv file gets reloaded and its styles reapplied, thus adding more and more buttons), and there also seems to be some recursion as the trace suggests when I hit Esc to exit.
I do get the warning that app1.kv is loaded multiple times, however, in the documentation for App.load_kv() it says
This method is invoked the first time the app is being run if no
widget tree has been constructed before for this app.
This implies to me that it should be possible to run() an app multiple times?
Here is my code:
main.py
from kivy.uix.widget import Widget
from kivy.uix.gridlayout import GridLayout
from kivy.app import App
from kivy.properties import ObjectProperty
from kivy.uix.button import Button
from kivy.clock import Clock
from kivy.logger import Logger
from kivy.lang import Builder
class OutsideApp(App):
current_app = ObjectProperty(None)
def build(self):
Clock.schedule_interval(self.update, 3)
return Widget()
def update(self, dt):
if isinstance(self.current_app, App):
self.current_app.stop()
if isinstance(self.current_app, App1):
self.current_app = App2()
else:
self.current_app = App1()
self.current_app.run()
class App1(App):
pass
class App2(App):
def build(self):
gl = Builder.load_string("<SequencesGame#GridLayout>:\n cols: 2\n Button:\n text: \"hello 2\"\nSequencesGame:")
return gl
if __name__ == '__main__':
oa = OutsideApp()
oa.run()
app1.kv
#:kivy 1.0.9
<SequencesGame#GridLayout>:
cols: 2
Button:
text: "hello 111"
SequencesGame:
This seems to be an issue even if apps are not nested:
main2.py
from kivy.app import App
from kivy.clock import Clock
from kivy.logger import Logger
from kivy.lang import Builder
class App1(App):
pass
class App2(App):
def build(self):
return Builder.load_string("<SequencesGame#GridLayout>:\n cols: 2\n Button:\n text: \"hello 2\"\nSequencesGame:")
current_app = None
def switch(*args):
global current_app
if isinstance(current_app, App):
current_app.stop()
if isinstance(current_app, App1):
current_app = App2()
else:
current_app = App1()
current_app.run()
if __name__ == '__main__':
Clock.schedule_interval(switch, 2)
switch()
In the end I followed #inclement's suggestion of using multiprocessing. Here is a basic implementation (without communication through Pipes or Queues):
import sys
import multiprocessing
from kivy.app import App
from kivy.lang import Builder
from time import sleep#, localtime, time
def str_to_class(str):
return reduce(getattr, str.split("."), sys.modules[__name__])
class App1(App):
def build(self):
return Builder.load_string("BoxLayout:\n Button:\n text: \"hello 1\"")
class App2(App):
def build(self):
return Builder.load_string("BoxLayout:\n Button:\n text: \"hello 2\"")
class Wrapper(object):
def __init__(self, *kargs, **kwargs):
super(Wrapper, self).__init__()
self.running_app = None
self.next_app = 'App1'
def change_running_app(self, name='App1'):
if self.running_app is not None:
self.running_app.terminate()
self.running_app = multiprocessing.Process(target=self.run_app, kwargs={'name':name})
self.running_app.start()
def run_app(self, name='App1'):
app = str_to_class(name)()
app.run()
def swap(self):
self.change_running_app(name=self.next_app)
self.next_app = ['App1', 'App2']['App1' is self.next_app]
if __name__ == '__main__':
counter = 0
w = Wrapper()
while True:
counter += 1
print "Started App instance {}".format(counter)
w.swap()
sleep(5)
Related
I am a beginner to Kivy (though not to Python), and I am struggling to get the ids from a kv string into my main code. I have the following, but the 'print' statement tells me that there are no IDs. The application itself runs with no errors.
import kivy
kivy.require('2.1.0')
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.gridlayout import GridLayout
from kivy.uix.image import Image
kvString = """
MainScreen:
id: maincontainer
cols: 1
thumbnails: thumbnails.__self__
GridLayout:
id: thumbnails
cols: 3
rows: 3
Image:
source: "test.png"
"""
class MainScreen(GridLayout):
def __init__(self, **kwargs):
super(MainScreen, self).__init__(**kwargs)
# This prints 0
print("Ids: {}".format(len(self.ids.items())))
class ExampleApp(App):
def build(self):
root = Builder.load_string(kvString)
return root
if __name__ == "__main__":
ExampleApp().run()
When I ran your code, I got a critical warning that there are no screens, and therefore the app will terminate. As soon as I switched MainScreen to a screen, it worked out perfectly. Here is the code:
.py
import kivy
kivy.require('2.1.0')
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.uix.image import Image
sm = ScreenManager()
#I removed some unnecessary code such as the cols, thumbnail, etc.
kvString = """
<MainScreen>
GridLayout:
id: thumbnails
cols: 3
rows: 3
Image:
source: "test.png"
"""
#NEEDS TO INHERIT SCREEN
class MainScreen(Screen):
def __init__(self, **kwargs):
super(MainScreen, self).__init__(**kwargs)
# This now prints 1
print(f'There are {len(self.ids.items())} id(s)')
class ExampleApp(App):
def build(self):
root = Builder.load_string(kvString)
#Adds the screen
sm.add_widget(MainScreen(name='screen'))
return sm
if __name__ == "__main__":
ExampleApp().run()
I'm trying to display an animation while something else is done in the background and I have this code:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from threading import Thread
from kivymd.app import MDApp
from kivy.animation import Animation
import multiprocessing
import time
sm = ScreenManager()
Builder.load_string("""
<LoadingScreen>:
BoxLayout:
Button:
id: loading_anim
text: 'Hello'
<MainLayout>:
BoxLayout:
Button:
text: 'world'
""")
class MainLayout(Screen):
pass
class LoadingScreen(Screen):
def __init__(self, **kwargs):
super().__init__(**kwargs)
def on_pre_enter(self):
t = multiprocessing.Process(target=self.loading_anim)
t.start()
t.join()
def loading_anim(self, *args):
print('sleeping after starting animation')
loading_anim = self.ids['loading_anim']
anim = Animation(
d=.7,
opacity=1
)
anim += Animation(
d=.7,
opacity=.6
)
time.sleep(1)
anim.repeat = True
anim.start(loading_anim)
time.sleep(1)
print('awake')
def prepare_for_launch(self, *args):
sm.switch_to(MainLayout(name='settings'))
class TestApp(MDApp):
def build(self):
sm.add_widget(LoadingScreen(name='menu'))
sm.add_widget(MainLayout(name='settings'))
return sm
if __name__ == '__main__':
TestApp().run()
but it throws an error saying:
"TypeError: no default __reduce__ due to non-trivial __cinit__"
but if I don't use multiprocessing it works.
Replace
def on_pre_enter(self):
t = multiprocessing.Process(target=self.loading_anim)
t.start()
t.join()
with
def on_pre_enter(self):
self.loading_anim
and it works fine. (the fact that animation starts after sleeping is done is concerning me too as I initiate it before sleeping.)
Struggling to pass a variable to kivy window. I have read similar threads all over the place but none of the fixes seem to work for me. Im sure this is simple to someone who knows their way around tiny, unfortunately I don't.
main.py
import kivy
from kivy.uix.togglebutton import ToggleButton
from kivy.app import App
from kivy.uix.gridlayout import GridLayout
from kivy.clock import Clock
from kivy.lang import Builder
from kivy.app import App
kivy.require('1.10.0')
from phue import Bridge
import nest
b = Bridge('xxx.xxx.x.xxx')
b.connect()
b.get_api()
lights = b.lights
class Controller(GridLayout):
print("launching")
def __init__(self):
super(Controller, self).__init__()
def KitchenSpot1(self,state):
lights[0].name
lights[0].on = state
def update(dt):
if b.get_light(1, 'on')== True:
#print("down") # When this line is commented out I get an continuous accurate update on the status of the light, showing that its working.
return 'down' # This is the part I want passed to the state criteria in the ivy window
else:
#print("up")# When this line is commented out I get an continuous accurate update on the status of the light, showing that its working.
return 'down' # This is the part I want passed to the state criteria in the ivy window
class ActionApp(App):
def build(self):
Clock.schedule_interval(Controller.update, 1.0 / 60.0)
return Controller()
myApp = ActionApp()
myApp.run()
action.kv
<Controller>:
cols: 4
rows: 3
spacing: 10
ToggleButton:
id: KitchenSpot1Toggle
text: "Kitchen Spot 1"
on_press: root.KitchenSpot1(True)
#on_release: root.KitchenSpot1(False)
#state1 = app.update.h
state: Controller.update # This is the part that is throwing up the error.
The error:
11: #on_release: root.KitchenSpot1(False)
12: #state1 = app.update.h
>> 13: state: Controller.update
14:
15:
...
NameError: name 'Controller' is not defined
Thanks in advance to anyone that can help me.
Make update an instance method and use a StringProperty to update state property in your kv:
main.py:
import kivy
kivy.require('1.10.0')
from kivy.app import App
from kivy.clock import Clock
from kivy.lang import Builder
from kivy.properties import StringProperty
from kivy.uix.gridlayout import GridLayout
from kivy.uix.togglebutton import ToggleButton
from phue import Bridge
import nest
b = Bridge('xxx.xxx.x.xxx')
b.connect()
b.get_api()
lights = b.lights
class Controller(GridLayout):
state = StringProperty('normal') # <<<<<<<<<<<<
def __init__(self, **kwargs):
super(Controller, self).__init__(**kwargs)
Clock.schedule_interval(self.update, 1.0 / 60.0)
def KitchenSpot1(self,state):
lights[0].name
lights[0].on = state
def update(self, dt):
if b.get_light(1, 'on'):
self.state = 'down' # <<<<<<<<<<<<
else:
self.state = 'normal' # <<<<<<<<<<<<
class ActionApp(App):
def build(self):
return Controller()
if __name__ == "__main__":
myApp = ActionApp()
myApp.run()
action.kv:
<Controller>:
cols: 4
rows: 3
spacing: 10
state: "normal" # <<<<<<<<<<<<
ToggleButton:
id: KitchenSpot1Toggle
text: "Kitchen Spot 1"
on_press: root.KitchenSpot1(True)
#on_release: root.KitchenSpot1(False)
#state1 = app.update.h
state: root.state # <<<<<<<<<<<<
Here is a more generic simplified answer from the kivy documentation, look for the section called "Keyword arguments and init()" because there are some other ways to do it as well.
The following code passes myvar to the build() method of MyApp. It does this by over-riding the init() of the Kivy App class by a new init() that calls App.init() and then continues with whatever extra initialisation you want. You can then store variables in the MyApp class instances and use them in build().
from kivy.app import App
from kivy.uix.label import Label
myvar = 'Hello Kivy'
class MyApp(App):
def __init__(self, myvar, **kwargs):
super(MyApp, self).__init__(**kwargs)
self.myvar = myvar
def build(self):
widget = Label(text=self.myvar)
return widget
if __name__ == '__main__':
MyApp(myvar).run()
I'm having issues with parsing a data structure to a widget in Kivy, which would then access the structure and be able to show a value on the screen be updated continuously via a clock interval (not sure of a better to do this yet).
I have highlighted the issues in the (non-working) code below:
main.py
from kivy.app import App
from test import TestWidget
class TestApp(App):
def build(self):
testStructTable = {'randomVal1': 1, 'testVal': 2, 'randomVal2': 3}
# Issue here parsing the table like this?
return TestWidget(testStructTable)
if __name__ == '__main__':
TestApp().run()
test.py
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.relativelayout import RelativeLayout
from kivy.properties import NumericProperty
class TestWidget(RelativeLayout):
def __init__(self, testStructTable, **kwargs):
super(TestWidget, self).__init__(**kwargs)
Builder.load_file('test.kv')
sm = ScreenManager()
sm.add_widget(MainScreen(name='MainScreen'))
self.add_widget(sm)
# Error accessing the table
print self.testStructTable
# Have the update_test_val continuously called
#Clock.schedule_interval(MainScreen.update_test_val(testStructTable), 1 / 60)
class MainScreen(Screen):
def __init__(self, **kwargs):
testVal = NumericProperty(0)
def update_test_val(self, testStructTable):
# Get testVal from testStructTable
# Something like:
# self.testVal = testStructTable.testVal + 1 ?
self.testVal = self.testVal + 1
test.kv
<MainScreen>:
FloatLayout:
Label:
text: str(root.testVal)
font_size: 80
My aim is to have the testVal constantly updating on the screen by accessing that data structure, however I am currently unable to achieve this, can you please advise?
In your __init__ method you're passing testStructTable and then you're trying to access self.testStructTable which does not exist untill you explicitly make an assignment:
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen
from kivy.uix.relativelayout import RelativeLayout
from kivy.properties import NumericProperty
class TestWidget(RelativeLayout):
def __init__(self, testStructTable, **kwargs):
super(TestWidget, self).__init__(**kwargs)
print(testStructTable)
self.testStructTable = testStructTable
print(self.testStructTable)
class TestApp(App):
def build(self):
testStructTable = {'randomVal1': 1, 'testVal': 2, 'randomVal2': 3}
# Issue here parsing the table like this?
return TestWidget(testStructTable)
if __name__ == '__main__':
TestApp().run()
So I want to build a kivy program that basically just countdown a certain minutes and seconds.
this is how far I have come:
from kivy.app import App
from kivy.uix.label import Label
from kivy.clock import Clock
from datetime import datetime, date, time
class IncrediblyCrudeClock(Label):
a = time(0, 1, 1)
def update(self, *args):
self.text = str(self.a)
print(str(self.a))
self.a = datetime.combine(date.today(), self.a) - datetime.combine(date.today(), time(0,0,1))
class TimeApp(App):
def build(self):
crudeclock = IncrediblyCrudeClock()
Clock.schedule_interval(crudeclock.update, 1)
return crudeclock
if __name__ == "__main__":
TimeApp().run()
the problem is that when I try to deduct the old time from the new time, sothat I have 1 second less displayed, I get the following error:
self.a = datetime.combine(date.today(), self.a) datetime.combine(date.today(), time(0,0,1))
TypeError: combine() argument 2 must be datetime.time, not datetime.timedelta
this makes me think that, after the first sustraction, a is now not a "time" object anymore, but a "timedelta" wich unfortunatly can not be deducted.
any help would be great!
There is a simpler approach if you just need a countdown. You can use kivy's Animation class which is described very nicely by #inclement on youtube.
So here's the code (main.py and time.kv):
main.py
from kivy.app import App
from kivy.uix.label import Label
from kivy.animation import Animation
from kivy.properties import StringProperty, NumericProperty
class IncrediblyCrudeClock(Label):
a = NumericProperty(5) # seconds
def start(self):
Animation.cancel_all(self) # stop any current animations
self.anim = Animation(a=0, duration=self.a)
def finish_callback(animation, incr_crude_clock):
incr_crude_clock.text = "FINISHED"
self.anim.bind(on_complete=finish_callback)
self.anim.start(self)
class TimeApp(App):
def build(self):
crudeclock = IncrediblyCrudeClock()
crudeclock.start()
return crudeclock
if __name__ == "__main__":
TimeApp().run()
time.kv
<IncrediblyCrudeClock>
text: str(round(self.a, 1))
Enjoy! :)
Update:
The OP requested a solution without a kv-file -- so here is one:
from kivy.app import App
from kivy.uix.label import Label
from kivy.animation import Animation
from kivy.properties import StringProperty, NumericProperty
class IncrediblyCrudeClock(Label):
a = NumericProperty(5) # seconds
def start(self):
Animation.cancel_all(self) # stop any current animations
self.anim = Animation(a=0, duration=self.a)
def finish_callback(animation, incr_crude_clock):
incr_crude_clock.text = "FINISHED"
self.anim.bind(on_complete=finish_callback)
self.anim.start(self)
def on_a(self, instance, value):
self.text = str(round(value, 1))
class TimeApp(App):
def build(self):
crudeclock = IncrediblyCrudeClock()
crudeclock.start()
return crudeclock
if __name__ == "__main__":
TimeApp().run()