Python：在使用多处理时更新 Tkinter
Python: Update Tkinter while using Multiprocessing
我遇到了以下问题：
我正在尝试使用 concurrent.futures.ProcessPoolExecutor() 或类似的东西，并在 tkinter 小部件上显示每个进程的进度。
有这个答案：
但我不能完全让它工作。
我的代码的以下简化版本似乎仅在使用我不想要的 ThreadPoolExecutor() 时才有效。
在此先感谢您的帮助！
import concurrent.futures
import tkinter
import tkinter.ttk
import multiprocessing
import random
import time
class App:
def __init__(self, root):
self.root = root
self.processes = 5
self.percentage = []
self.changing_labels = []
self.queues = []
self.values = []
for i in range(self.processes):
temp_percentage = tkinter.StringVar()
temp_percentage.set("0 %")
self.percentage.append(temp_percentage)
temp_changing_label = tkinter.Label(self.root, textvariable=temp_percentage)
temp_changing_label.pack()
self.changing_labels.append(temp_changing_label)
self.queues.append(multiprocessing.Queue())
# Just same values that I want to do calculations on
temp_value = []
for ii in range(12):
temp_value.append(random.randrange(10))
self.values.append(temp_value.copy())
self.start_processing()
def start_processing(self):
def save_values(my_values): # Save my new calculated values on the same file or different file
with open(f"example.txt", "a") as file:
for v in my_values:
file.write(str(v))
file.write(" ")
file.write("\n")
def work(my_values, my_queue): # Here I do all my work
# Some values to calculate my progress so that I can update my Labels
my_progress = 0
step = 100 / len(my_values)
# Do some work on the values
updated_values = []
for v in my_values:
time.sleep(0.5)
updated_values.append(v + 1)
my_progress += step
my_queue.put(my_progress) # Add current progress to queue
save_values(updated_values) # Save it before exiting
# This Part does no work with ProcessPoolExecutor, with ThreadPoolExecutor it works fine
with concurrent.futures.ProcessPoolExecutor() as executor:
results = [executor.submit(work, self.values[i], self.queues[i])
for i in range(self.processes)]
# Run in a loop and update Labels or exit when done
while True:
results_done = [result.done() for result in results]
if False in results_done:
for i in range(self.processes):
if results_done[i] is False:
if not self.queues[i].empty():
temp_queue = self.queues[i].get()
self.percentage[i].set(f"{temp_queue:.2f} %")
else:
self.percentage[i].set("100 %")
self.root.update()
else:
break
# Close window at the very end
self.root.destroy()
def main(): # Please do not change my main unless it is essential
root = tkinter.Tk()
my_app = App(root)
root.mainloop()
if __name__ == "__main__":
main()
问题是由新进程中抛出的异常引起的。要查看此异常，您可以调用引发异常的 Future.result 函数，例如
print([result.result() for result in results])
这给出了错误 AttributeError: Can't pickle local object 'App.start_processing.<locals>.work'，所以问题是 work 是在另一个函数中定义的。
将 work 和 save_values 函数移出 start_processing 方法后，错误变为 RuntimeError: Queue objects should only be shared between processes through inheritance。这可以通过使用 multiprocessing.Manager 创建队列来解决：
class App:
def __init__(self, root):
...
with multiprocessing.Manager() as manager:
for i in range(self.processes):
...
self.queues.append(manager.Queue())
...
self.start_processing()
现在可以删除 print([result.result() for result in results]) 调试行。
完整代码如下：
import concurrent.futures
import tkinter
import tkinter.ttk
import multiprocessing
import random
import time
class App:
def __init__(self, root):
self.root = root
self.processes = 5
self.percentage = []
self.changing_labels = []
self.queues = []
self.values = []
with multiprocessing.Manager() as manager:
for i in range(self.processes):
temp_percentage = tkinter.StringVar()
temp_percentage.set("0 %")
self.percentage.append(temp_percentage)
temp_changing_label = tkinter.Label(self.root, textvariable=temp_percentage)
temp_changing_label.pack()
self.changing_labels.append(temp_changing_label)
self.queues.append(manager.Queue())
# Just same values that I want to do calculations on
temp_value = []
for ii in range(12):
temp_value.append(random.randrange(10))
self.values.append(temp_value.copy())
self.start_processing()
@staticmethod
def save_values(my_values): # Save my new calculated values on the same file or different file
with open(f"example.txt", "a") as file:
for v in my_values:
file.write(str(v))
file.write(" ")
file.write("\n")
@classmethod
def work(cls, my_values, my_queue): # Here I do all my work
# Some values to calculate my progress so that I can update my Labels
my_progress = 0
step = 100 / len(my_values)
# Do some work on the values
updated_values = []
for v in my_values:
time.sleep(0.5)
updated_values.append(v + 1)
my_progress += step
my_queue.put(my_progress) # Add current progress to queue
cls.save_values(updated_values) # Save it before exiting
def start_processing(self):
# This Part does no work with ProcessPoolExecutor, with ThreadPoolExecutor it works fine
with concurrent.futures.ProcessPoolExecutor() as executor:
results = [executor.submit(self.work, self.values[i], self.queues[i])
for i in range(self.processes)]
# Run in a loop and update Labels or exit when done
while True:
results_done = [result.done() for result in results]
if False in results_done:
for i in range(self.processes):
if results_done[i] is False:
if not self.queues[i].empty():
temp_queue = self.queues[i].get()
self.percentage[i].set(f"{temp_queue:.2f} %")
else:
self.percentage[i].set("100 %")
self.root.update()
else:
break
# Close window at the very end
self.root.destroy()
def main(): # Please do not change my main unless it is essential
root = tkinter.Tk()
my_app = App(root)
root.mainloop()
if __name__ == "__main__":
main()
PS：我推荐not all(results_done)而不是False in results_done，not results_done[i]而不是results_done[i] is False。
我遇到了以下问题：
我正在尝试使用 concurrent.futures.ProcessPoolExecutor() 或类似的东西，并在 tkinter 小部件上显示每个进程的进度。
有这个答案：
我的代码的以下简化版本似乎仅在使用我不想要的 ThreadPoolExecutor() 时才有效。
在此先感谢您的帮助！
import concurrent.futures
import tkinter
import tkinter.ttk
import multiprocessing
import random
import time
class App:
def __init__(self, root):
self.root = root
self.processes = 5
self.percentage = []
self.changing_labels = []
self.queues = []
self.values = []
for i in range(self.processes):
temp_percentage = tkinter.StringVar()
temp_percentage.set("0 %")
self.percentage.append(temp_percentage)
temp_changing_label = tkinter.Label(self.root, textvariable=temp_percentage)
temp_changing_label.pack()
self.changing_labels.append(temp_changing_label)
self.queues.append(multiprocessing.Queue())
# Just same values that I want to do calculations on
temp_value = []
for ii in range(12):
temp_value.append(random.randrange(10))
self.values.append(temp_value.copy())
self.start_processing()
def start_processing(self):
def save_values(my_values): # Save my new calculated values on the same file or different file
with open(f"example.txt", "a") as file:
for v in my_values:
file.write(str(v))
file.write(" ")
file.write("\n")
def work(my_values, my_queue): # Here I do all my work
# Some values to calculate my progress so that I can update my Labels
my_progress = 0
step = 100 / len(my_values)
# Do some work on the values
updated_values = []
for v in my_values:
time.sleep(0.5)
updated_values.append(v + 1)
my_progress += step
my_queue.put(my_progress) # Add current progress to queue
save_values(updated_values) # Save it before exiting
# This Part does no work with ProcessPoolExecutor, with ThreadPoolExecutor it works fine
with concurrent.futures.ProcessPoolExecutor() as executor:
results = [executor.submit(work, self.values[i], self.queues[i])
for i in range(self.processes)]
# Run in a loop and update Labels or exit when done
while True:
results_done = [result.done() for result in results]
if False in results_done:
for i in range(self.processes):
if results_done[i] is False:
if not self.queues[i].empty():
temp_queue = self.queues[i].get()
self.percentage[i].set(f"{temp_queue:.2f} %")
else:
self.percentage[i].set("100 %")
self.root.update()
else:
break
# Close window at the very end
self.root.destroy()
def main(): # Please do not change my main unless it is essential
root = tkinter.Tk()
my_app = App(root)
root.mainloop()
if __name__ == "__main__":
main()
问题是由新进程中抛出的异常引起的。要查看此异常，您可以调用引发异常的 Future.result 函数，例如
print([result.result() for result in results])
这给出了错误 AttributeError: Can't pickle local object 'App.start_processing.<locals>.work'，所以问题是 work 是在另一个函数中定义的。
将 work 和 save_values 函数移出 start_processing 方法后，错误变为 RuntimeError: Queue objects should only be shared between processes through inheritance。这可以通过使用 multiprocessing.Manager 创建队列来解决：
class App:
def __init__(self, root):
...
with multiprocessing.Manager() as manager:
for i in range(self.processes):
...
self.queues.append(manager.Queue())
...
self.start_processing()
现在可以删除 print([result.result() for result in results]) 调试行。
完整代码如下：
import concurrent.futures
import tkinter
import tkinter.ttk
import multiprocessing
import random
import time
class App:
def __init__(self, root):
self.root = root
self.processes = 5
self.percentage = []
self.changing_labels = []
self.queues = []
self.values = []
with multiprocessing.Manager() as manager:
for i in range(self.processes):
temp_percentage = tkinter.StringVar()
temp_percentage.set("0 %")
self.percentage.append(temp_percentage)
temp_changing_label = tkinter.Label(self.root, textvariable=temp_percentage)
temp_changing_label.pack()
self.changing_labels.append(temp_changing_label)
self.queues.append(manager.Queue())
# Just same values that I want to do calculations on
temp_value = []
for ii in range(12):
temp_value.append(random.randrange(10))
self.values.append(temp_value.copy())
self.start_processing()
@staticmethod
def save_values(my_values): # Save my new calculated values on the same file or different file
with open(f"example.txt", "a") as file:
for v in my_values:
file.write(str(v))
file.write(" ")
file.write("\n")
@classmethod
def work(cls, my_values, my_queue): # Here I do all my work
# Some values to calculate my progress so that I can update my Labels
my_progress = 0
step = 100 / len(my_values)
# Do some work on the values
updated_values = []
for v in my_values:
time.sleep(0.5)
updated_values.append(v + 1)
my_progress += step
my_queue.put(my_progress) # Add current progress to queue
cls.save_values(updated_values) # Save it before exiting
def start_processing(self):
# This Part does no work with ProcessPoolExecutor, with ThreadPoolExecutor it works fine
with concurrent.futures.ProcessPoolExecutor() as executor:
results = [executor.submit(self.work, self.values[i], self.queues[i])
for i in range(self.processes)]
# Run in a loop and update Labels or exit when done
while True:
results_done = [result.done() for result in results]
if False in results_done:
for i in range(self.processes):
if results_done[i] is False:
if not self.queues[i].empty():
temp_queue = self.queues[i].get()
self.percentage[i].set(f"{temp_queue:.2f} %")
else:
self.percentage[i].set("100 %")
self.root.update()
else:
break
# Close window at the very end
self.root.destroy()
def main(): # Please do not change my main unless it is essential
root = tkinter.Tk()
my_app = App(root)
root.mainloop()
if __name__ == "__main__":
main()
PS：我推荐not all(results_done)而不是False in results_done，not results_done[i]而不是results_done[i] is False。