[英]Global Variable not working with Threads - Python
I want to be able to change the background colour of a Tkinter frame in a thread, the frame is declared in a separate function.我希望能够在线程中更改 Tkinter 框架的背景颜色,该框架是在单独的函数中声明的。 I receive the following error when I run the following code.
运行以下代码时收到以下错误。
Error: NameError: name 'mainScreen' is not defined
错误:
NameError: name 'mainScreen' is not defined
Code:代码:
import tkinter as tk
from tkinter import ttk
from multiprocessing import Process
def main():
global mainScreen
root = tk.Tk()
root.geometry('1040x540+50+50')
mainScreen = tk.Frame(root, width = 1040, height = 540)
mainScreen.place(x=0, y=0)
root.mainloop()
def test(): # This function is in a thread as it will be run as a loop.
while True:
mainScreen.configure(bg='red')
if __name__ == '__main__':
p2 = Process(target = test)
p2.start()
main()
Any help is appreciated.任何帮助表示赞赏。
You can replace your whole code with this:你可以用这个替换你的整个代码:
import tkinter as tk
def main():
global mainScreen
root = tk.Tk()
root.geometry('1040x540+50+50')
mainScreen = tk.Frame(root, width=1040, height=540)
mainScreen.place(x=0, y=0)
mainScreen.configure(bg='red')
root.mainloop()
if __name__ == '__main__':
main()
And if you want to change colours you can do something like this:如果你想改变颜色,你可以这样做:
import time
import tkinter as tk
from threading import Thread
def test(mainScreen): # This function is in a thread as it will be run as a loop.
while True:
try:
time.sleep(1)
mainScreen.configure(bg='red')
time.sleep(1)
mainScreen.configure(bg='blue')
except RuntimeError:
break
if __name__ == '__main__':
root = tk.Tk()
root.geometry('1040x540+50+50')
mainScreen = tk.Frame(root, width=1040, height=540)
mainScreen.place(x=0, y=0)
p2 = Thread(target=test, args=(mainScreen,))
p2.start()
root.mainloop()
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