使用 Tkinter 时 while 循环不起作用 [英] While loop not working while using Tkinter

问题描述

我有一个 BASH 脚本正在运行，它打开一个程序 (tshark)，该程序将一堆值写入日志文件.然后脚本计算唯一值并将过去 3 分钟的(计数)唯一值写入日志文件 (count3m.log) 它还打开一个 python 脚本.python 用于显示一个窗口，其中包含来自 count3m.log 的值.由于 count3m.log 中的值每 30 秒更改一次，我想继续从 count3m 中寻找新值.我用下面的代码试过了.它只执行一次循环.我做错了什么?

I have a BASH script running that opens a program (tshark) which writes a bunch of values to a logfile. The script then counts the unique values and writes the (count of the) uniques values from the last 3 minutes to a logfile (count3m.log) It also opens a python script. The python is there to show a window with the values from count3m.log. As the value in count3m.log changes every 30 seconds I want to keep looking for a new value from count3m. I tried it with the code below. It only executes the loop once. What am I doing wrong?

#!/usr/bin/env python

import sys
import re
import time
from Tkinter import *

while True:  

    root = Tk()
    count3m = open('count3m.log','r')
    countStart = open('countStart.log','r')


    minutes = Label(root, text="Uniq signals < 3m ago:")
    minutes.grid(row=0, column=0)

    minutes = Label(root, text=count3m.read())
    minutes.grid(row=1, column=0)
    count3m.close

    minutes = Label(root, text="Uniq signals since start:")
    minutes.grid(row=0, column=1)

    minutes = Label(root, text=countStart.read())
    minutes.grid(row=1, column=1)
    countStart.close
    time.sleep(5)
    print "test"
    root.mainloop()

推荐答案

参考这个 答案

mainloop 实际上只不过是一个大致如下所示的无限循环(这些不是方法的实际名称，名称仅用于说明这一点):

mainloop is really nothing more than an infinite loop that looks roughly like this (those aren't the actual names of the methods, the names merely serve to illustrate the point):

while True:
    event=wait_for_event()
    event.process()
    if main_window_has_been_destroyed(): 
        break

所以，你的循环中有一个无限循环.

So, you have an infinite loop inside your loop.

为了更新您的标签，您需要将一个事件附加到您的根目录.另外，设置标签的 textvariable = a StringVar.然后，更新事件中的StringVar，它会改变标签.

In order to update your label, you'll need to attach an event to your root. Also, set your label's textvariable = a StringVar. Then, update the StringVar in the event, and it will change the label.

像这样

text  = StringVar()
label = Label(root, textvariable=text)
label.pack()

def update_label():
  text.set("new stuff")
  #update again
  root.after(SOME_TIME, update_label)

#the first update
root.after(SOME_TIME, update_label)
root.mainloop()

这应该给你基本的想法.相关堆栈溢出问题:

That should give you the basic idea. Relate stack overflow questions:

使 python/tkinter 标签小部件更新?

Python:当函数在后台运行时，是否可以创建一个具有动态字符串的 tkinter 标签?

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