我尝试使用Tkinter GUI启动子进程并将其stdout / stderr输出显示到Text小部件。最初，我认为通过设置＆＃34; sys.stdout = text_widget＆＃34;可以轻松地将sys.stdout重定向到Text小部件。但似乎没有。它出现了一个错误：＆＃34;文本实例没有属性＆＃39; flush＆＃39;＆＃34;。
我在网上查了一下，得到了一些解决方案，比如使用Queue与子进程进行通信。但是，由于我的特殊要求，它们都不适合我的情况：
在这种情况下，任何人都可以找到一个获得＆＃34;多处理的过程的解决方案。过程＆＃34;＆＃34;打印＆＃34;输出并显示到Tkinter文本？非常感谢！
我的案例的示例代码如下：
import sys
import time
from multiprocessing import Process
from Tkinter import *
def test_child():
print 'child running'
def test_parent():
print 'parent running'
time.sleep(0.5)
Process(target=test_child).start()
def set_txt(msg):
gui_txt.insert(END, str(msg))
gui_txt.see(END)
if __name__ == '__main__':
gui_root = Tk()
gui_txt = Text(gui_root)
gui_txt.pack()
gui_btn = Button(gui_root, text='Test', command=test_parent)
gui_btn.pack()
gui_txt.write = set_txt
sys.stdout = gui_txt
gui_root.mainloop()
答案 0 :(得分：3)
仍然可以使用队列而不必删除所有print语句。您可以使用Process依赖stdout重定向来执行此操作。下面的解决方案使用Queue子类来模仿stdout。然后，该队列由一个线程监视，该线程查找被泵入文本小部件的新文本。
import sys
import time
from multiprocessing import Process
from multiprocessing.queues import Queue
from threading import Thread
from Tkinter import *
# This function takes the text widget and a queue as inputs.
# It functions by waiting on new data entering the queue, when it
# finds new data it will insert it into the text widget
def text_catcher(text_widget,queue):
while True:
text_widget.insert(END, queue.get())
# This is a Queue that behaves like stdout
class StdoutQueue(Queue):
def __init__(self,*args,**kwargs):
Queue.__init__(self,*args,**kwargs)
def write(self,msg):
self.put(msg)
def flush(self):
sys.__stdout__.flush()
def test_child(q):
# This line only redirects stdout inside the current process
sys.stdout = q
# or sys.stdout = sys.__stdout__ if you want to print the child to the terminal
print 'child running'
def test_parent(q):
# Again this only redirects inside the current (main) process
# commenting this like out will cause only the child to write to the widget
sys.stdout = q
print 'parent running'
time.sleep(0.5)
Process(target=test_child,args=(q,)).start()
if __name__ == '__main__':
gui_root = Tk()
gui_txt = Text(gui_root)
gui_txt.pack()
q = StdoutQueue()
gui_btn = Button(gui_root, text='Test', command=lambda:test_parent(q),)
gui_btn.pack()
# Instantiate and start the text monitor
monitor = Thread(target=text_catcher,args=(gui_txt,q))
monitor.daemon = True
monitor.start()
gui_root.mainloop()
答案 1 :(得分：0)
@ebarr给出的解决方案是正确的。但它不适用于Python V5或更高版本。当您尝试子类化multiprocessing.queues.Queue类时，您将收到以下错误：
C:\Users\..\myFolder > python myTest.py
Traceback (most recent call last):
File "myTest.py", line 49, in <module>
q = StdoutQueue()
File "myTest.py", line 22, in __init__
super(StdoutQueue,self).__init__(*args,**kwargs)
TypeError: __init__() missing 1 required keyword-only argument: 'ctx'
您需要明确地为子类队列提供“多处理上下文”。
以下是更新后的代码：
import sys
import time
import multiprocessing as mp
import multiprocessing.queues as mpq
from threading import Thread
from tkinter import *
'''-------------------------------------------------------------------'''
''' SUBCLASSING THE MULTIPROCESSING QUEUE '''
''' '''
''' ..and make it behave as a general stdout io '''
'''-------------------------------------------------------------------'''
# The StdoutQueue is a Queue that behaves like stdout.
# We will subclass the Queue class from the multiprocessing package
# and give it the typical stdout functions.
#
# (1) First issue
# Subclassing multiprocessing.Queue or multiprocessing.SimpleQueue
# will not work, because these classes are not genuine
# python classes.
# Therefore, you need to subclass multiprocessing.queues.Queue or
# multiprocessing.queues.SimpleQueue . This issue is known, and is not
# the reason for asking this question. But I mention it here, for
# completeness.
#
# (2) Second issue
# There is another problem that arises only in Python V5 (and beyond).
# When subclassing multiprocessing.queues.Queue, you have to provide
# a 'multiprocessing context'. Not doing that, leads to an obscure error
# message, which is in fact the main topic of this question. Darth Kotik
# solved it.
# His solution is visible in this code:
class StdoutQueue(mpq.Queue):
def __init__(self,*args,**kwargs):
ctx = mp.get_context()
super(StdoutQueue, self).__init__(*args, **kwargs, ctx=ctx)
def write(self,msg):
self.put(msg)
def flush(self):
sys.__stdout__.flush()
'''-------------------------------------------------------------------'''
''' TEST SETUP '''
'''-------------------------------------------------------------------'''
# This function takes the text widget and a queue as inputs.
# It functions by waiting on new data entering the queue, when it
# finds new data it will insert it into the text widget.
def text_catcher(text_widget,queue):
while True:
text_widget.insert(END, queue.get())
def test_child(q):
# This line only redirects stdout inside the current process
sys.stdout = q
# or sys.stdout = sys.__stdout__ if you want to print the child to the terminal
print('child running')
def test_parent(q):
# Again this only redirects inside the current (main) process
# commenting this like out will cause only the child to write to the widget
sys.stdout = q
print('parent running')
time.sleep(0.5)
mp.Process(target=test_child,args=(q,)).start()
if __name__ == '__main__':
gui_root = Tk()
gui_txt = Text(gui_root)
gui_txt.pack()
q = StdoutQueue()
gui_btn = Button(gui_root, text='Test', command=lambda:test_parent(q),)
gui_btn.pack()
# Instantiate and start the text monitor
monitor = Thread(target=text_catcher,args=(gui_txt,q))
monitor.daemon = True
monitor.start()
gui_root.mainloop()
有关详细信息，请参阅此主题：Cannot subclass multiprocessing Queue in Python 3.5