从另一个线程更改kivy属性 [英] Altering a kivy property from another thread
问题描述
我正在尝试一些奇异的代码.我尝试从使用线程库创建的胎面修改kivy属性(text_colour).程序工作正常，但线程不会更改属性.
I'm experimenting with some kivy code. I tried modifing a kivy property(text_colour) from a tread created with threading lib. Program works fine but the thread does not change the property.
我还尝试在类中创建一个方法，该方法将值作为参数获取，这也失败了.
I also tried to create a method in class about which gets the value as an argument, which also failed.
from kivy.app import App
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ListProperty
import threading
import random
import time
def zaaa():
import time
time.sleep(3)
ScatterTextWidget.text_colour = [0, 0, 1, 1]
print "function ran"
t = threading.Thread(target= zaaa)
t.start()
class ScatterTextWidget(BoxLayout):
text_colour = ListProperty([1, 0, 0, 1])
def change_label_colour(self, *args):
colour = [random.random() for i in xrange(3)] + [1]
self.text_colour = colour
def press(self, *args):
self.text_colour = [1, 1, 1, 1]
class TataApp(App):
def build(self):
return ScatterTextWidget()
if __name__ == "__main__":
TataApp().run()
输出:
[INFO ] Kivy v1.8.0
[INFO ] [Logger ] Record log in /home/mbp/.kivy/logs/kivy_14-02-26_44.txt
[INFO ] [Factory ] 157 symbols loaded
[DEBUG ] [Cache ] register <kv.lang> with limit=None, timeout=Nones
[DEBUG ] [Cache ] register <kv.image> with limit=None, timeout=60s
[DEBUG ] [Cache ] register <kv.atlas> with limit=None, timeout=Nones
[INFO ] [Image ] Providers: img_tex, img_dds, img_pygame, img_pil, img_gif
[DEBUG ] [Cache ] register <kv.texture> with limit=1000, timeout=60s
[DEBUG ] [Cache ] register <kv.shader> with limit=1000, timeout=3600s
[DEBUG ] [App ] Loading kv </home/mbp/workspace/KiviPlay/tata.kv>
[DEBUG ] [Window ] Ignored <egl_rpi> (import error)
[INFO ] [Window ] Provider: pygame(['window_egl_rpi'] ignored)
libpng warning: iCCP: known incorrect sRGB profile
[DEBUG ] [Window ] Display driver x11
[DEBUG ] [Window ] Actual window size: 800x600
[DEBUG ] [Window ] Actual color bits r8 g8 b8 a8
[DEBUG ] [Window ] Actual depth bits: 24
[DEBUG ] [Window ] Actual stencil bits: 8
[DEBUG ] [Window ] Actual multisampling samples: 2
[INFO ] [GL ] OpenGL version <4.3.12618 Compatibility Profile Context 13.251>
[INFO ] [GL ] OpenGL vendor <ATI Technologies Inc.>
[INFO ] [GL ] OpenGL renderer <AMD Radeon HD 7700 Series>
[INFO ] [GL ] OpenGL parsed version: 4, 3
[INFO ] [GL ] Shading version <4.30>
[INFO ] [GL ] Texture max size <16384>
[INFO ] [GL ] Texture max units <32>
[DEBUG ] [Shader ] Fragment compiled successfully
[DEBUG ] [Shader ] Vertex compiled successfully
[DEBUG ] [ImagePygame ] Load </usr/lib/python2.7/site-packages/Kivy-1.8.0-py2.7-linux-x86_64.egg/kivy/data/glsl/default.png>
[INFO ] [Window ] virtual keyboard not allowed, single mode, not docked
[INFO ] [Text ] Provider: pygame
[DEBUG ] [Cache ] register <kv.loader> with limit=500, timeout=60s
[INFO ] [Loader ] using a thread pool of 2 workers
[DEBUG ] [Cache ] register <textinput.label> with limit=None, timeout=60.0s
[DEBUG ] [Cache ] register <textinput.width> with limit=None, timeout=60.0s
[DEBUG ] [Atlas ] Load </usr/lib/python2.7/site-packages/Kivy-1.8.0-py2.7-linux-x86_64.egg/kivy/data/../data/images/defaulttheme.atlas>
[DEBUG ] [Atlas ] Need to load 1 images
[DEBUG ] [Atlas ] Load </usr/lib/python2.7/site-packages/Kivy-1.8.0-py2.7-linux-x86_64.egg/kivy/data/../data/images/defaulttheme-0.png>
[DEBUG ] [ImagePygame ] Load </usr/lib/python2.7/site-packages/Kivy-1.8.0-py2.7-linux-x86_64.egg/kivy/data/../data/images/defaulttheme-0.png>
[INFO ] [GL ] NPOT texture support is available
[INFO ] [OSC ] using <multiprocessing> for socket
[DEBUG ] [Base ] Create provider from mouse
[DEBUG ] [Base ] Create provider from probesysfs
[DEBUG ] [ProbeSysfs ] using probsysfs!
[INFO ] [Base ] Start application main loop
<kivy.properties.ListProperty object at 0x124f870>
function ran
[INFO ] [Base ] Leaving application in progress...
推荐答案
您无法通过外部线程修改kivy属性或进行任何与OpenGL相关的工作.
You cannot modify a kivy property or do any OpenGL related work from an external thread.
解决方案是安排回调与kivy的Clock一起调用函数从kivy的主线程开始，然后为您完成工作.
The solution is to schedule callbacks with kivy's Clock that will call a function from kivy's main thread and do the work for you.
就我个人而言，当我使用第二个线程时，我对线程间通信使用队列，如下所示:
Personally, when I use a second thread, I use a queue for the inter-thread comm as follows:
from Queue import Queue
class KivyQueue(Queue):
'''
A Multithread safe class that calls a callback whenever an item is added
to the queue. Instead of having to poll or wait, you could wait to get
notified of additions.
>>> def callabck():
... print('Added')
>>> q = KivyQueue(notify_func=callabck)
>>> q.put('test', 55)
Added
>>> q.get()
('test', 55)
:param notify_func: The function to call when adding to the queue
'''
notify_func = None
def __init__(self, notify_func, **kwargs):
Queue.__init__(self, **kwargs)
self.notify_func = notify_func
def put(self, key, val):
'''
Adds a (key, value) tuple to the queue and calls the callback function.
'''
Queue.put(self, (key, val), False)
self.notify_func()
def get(self):
'''
Returns the next items in the queue, if non-empty, otherwise a
:py:attr:`Queue.Empty` exception is raised.
'''
return Queue.get(self, False)
第二个线程使用put将事物放到队列中.回调在被调用时，会使用触发. kivy的主线程随后调用的函数将调用队列的get函数并设置适当的属性.
The second threads uses put to put things on the queue. And the callback, when called, schedules a kivy callback using a trigger. The function that the kivy's main thread then calls calls the get function of the queue and sets the appropriate property.
如果您需要设置许多属性，这将很有帮助.如果您只需要设置一个属性，那么我将从第二个线程中计划一个callabck，该callabck使用partial来使值成为函数的一部分.例如:
That is helpful if you need to set many properties. If you just need to set a single property, what I do is from the second thread I schedule a callabck that uses partial to make the value part of the function. E.g:
# this may only be called from the main kivy thread
def set_property(value, *largs):
self.kivy_property = value
# the second thread does this when it wants to set self.kivy_property to 10
Clock.schedule_once(partial(set_property, 10))
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