問題描述
我正在嘗試一些 kivy 代碼.我嘗試從使用線程庫創建的胎面修改 kivy 屬性(text_colour).程序運行正常，但線程沒有改變屬性.
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.
我還嘗試在類中創建一個將值作為參數的方法，但也失敗了.
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()
輸出:
[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...
推薦答案
您不能從外部線程修改 kivy 屬性或執行任何與 OpenGL 相關的工作.
You cannot modify a kivy property or do any OpenGL related work from an external thread.
解決方案是用 kivy 的 Clock 來安排 callbacks 來調用一個函數來自 kivy 的主線程并為您完成工作.
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.
就個人而言，當我使用第二個線程時，我使用隊列進行線程間通信，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)
第二個線程使用 put 將東西放入隊列.回調在調用時會使用 trigger.然后kivy的主線程調用的函數調用隊列的get函數并設置相應的屬性.
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.
如果您需要設置許多屬性，這將很有幫助.如果您只需要設置一個屬性，我所做的就是從第二個線程中安排一個 callabck，它使用 partial 來使 value 成為函數的一部分.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))
這篇關于從另一個線程更改 kivy 屬性的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！