时钟实例

from tkinter import *
from time import  strftime

root = Tk()
root.title('时钟')

lbl = Label(root, font = ('arial',300,'bold'), bg = 'black', fg = 'white')
lbl.pack(anchor = 'center', fill = 'both', expand = 1)

mode = 'hour'

def showtime():
    if mode == 'hour':
        string = strftime('%H:%M:%S %p')
    else:
        string = strftime("%Y-%m-%d")

    lbl.config(text=string)
    lbl.after(1000,showtime)  # 1秒后执行 time 函数

def  mouse_click(event):
    global mode
    if mode == 'hour':
        mode = 'day'
    else:
        mode = 'hour'
    print(mode)

lbl.bind("<Button>", mouse_click)

showtime()

mainloop()