基于tkinter的点名

import datetime
import random
import tkinter as tk
import time




class chas_lp():
    def __init__(self):
        self.tr=tk.Tk()
        self.tr.title('点名')
        self.tr.geometry('500x200')
        self.qew3=tk.StringVar()
        self.lp=['qwe','qwe1','zxc','fgh','rty']
        self.a=0
        self.c=0



    def qwe2(self):

        self.qew3.set(self.lp[self.a])
        xcv=self.tr.after(100,self.qwe2)
        self.a+=1
        if self.a==len(self.lp):
            self.a=0
        if self.c%2!=0:
              self.tr.after_cancel(xcv)


    def fgh(self):
        self.c+=1
        if self.c%2==0:
            self.qwe2()
        print(self.c)

    def qwe11(self):
        # self.qwe2()
        bhu=tk.Label(self.tr,textvariable=self.qew3,font=('黑体',30),fg='red')
        bhu.pack()
        qwe=tk.Button(self.tr,text='停止',width=10,height=5,command=lambda :self.fgh())
        qwe.pack()
        self.qwe2()
        self.tr.mainloop()


if __name__ == '__main__':
    chang_op=chas_lp()
    chang_op.qwe11()