#!/usr/bin/python3.8# -*- coding: utf-8 -*-# @Time    : 2021/4/19 14:09# @Author  : dongdong# @File    : CountdownGUI.py# @Software: PyCharmfrom tkinter import *import timeimport threadingdef cyclethread():    global counttime    global restartflag    global runflag    restartflag=False    if (timestr.get().isdigit()):        counttime = int(timestr.get()) * 60    else:        runflag=False        return;    while (1):        if(restartflag):            counttime = int(timestr.get()) * 60            restartflag=False        if(exitflag):            sys.exit()        counttime=counttime-1        v='/nleft time:'+str(counttime//60)+' :'+str(counttime%60)        textshow.set(v)        root.update()        if (counttime <= 0):            runflag = False            return        time.sleep(1)def startCount():    global  restartflag    global runflag    restartflag=True    if( not runflag):        th=threading.Thread(target=cyclethread)        th.setDaemon(True)        th.start()        runflag = Truedef exitfun():    global exitflag    exitflag=True    sys.exit()restartflag=Falseexitflag=Falsecounttime=Nonerunflag=Falseroot=Tk()root.geometry('250x120')root.title('TimeCounter')timestr = StringVar(value="30")textshow=StringVar(value='/nCountDown:30min ')text0=Label(root,text='Input time(min):').grid(row=0,column=0,columnspan=3)entext=Entry(root,textvariable=timestr).grid(row=0,column=3,columnspan=1)# bnframe=ttk.Frame(root).grid(row=1,column=0,columnspan=4)stbn=Button(root,text='Start',command=startCount).grid(row=1,column=2,columnspan=1)enbn=Button(root,text='Exit',command=exitfun).grid(row=1,column=3,columnspan=1)text=Label(root,textvariable=textshow).grid(row=2,column=0,columnspan=4)root.mainloop()