如何检查进程是否已完成但无需等待？

Question

我正在 python/tkinter 中做一个小项目，我一直在寻找一种方法来检查进程是否已完成但“无需等待”。我试过了：

process = subprocess.Popen(command)
while process.poll() is None:
    print('Running!')
print('Finished!')

或：

process = subprocess.Popen(command)
stdoutdata, stderrdata = process.communicate()
print('Finished!')

两个代码都执行命令并打印“完成！”当进程结束时，但主程序冻结（等待），这就是我想要避免的。 我需要 GUI 在进程运行时保持功能，然后在它完成后立即运行一些代码。有什么帮助吗？

Answer 1

您通常会为此目的使用 Thread 模块：

例如：

# import Thread
from threading import Thread
import time

# create a function that checks if the process has finished
process = True
def check():
    while process:
        print('Running')
        time.sleep(1) # here you can wait as much as you want without freezing the program
    else:
        print('Finished')

# call the function with the use of Thread
Thread(target=check).start()
# or if you want to keep a reference to it
t = Thread(target=check)
# you might also want to set thread daemon to True so as the Thread ends when the program closes
t.deamon = True
t.start()

这样，当您执行process=False 时，程序将结束并且输出将显示'Finished'