python开发的简单窗口界面的倒计时界面

# Countdown using Tkinter
from Tkinter import *
import time
import tkMessageBox
class App:
    def init(self,master):
        frame = Frame(master)
        frame.pack()
        self.entryWidget = Entry(frame)
        self.entryWidget["width"] = 15
        self.entryWidget.pack(side=LEFT)
        self.hi_there = Button(frame, text="Start", command=self.start)
        self.hi_there.pack(side=LEFT)
        self.button = Button(frame, text="QUIT", fg="red", command=frame.quit)
        self.button.pack(side=LEFT)

def start(self):
    text = self.entryWidget.get().strip()
    if text != "":
        num = int(text)
        self.countDown(num)

def countDown(self,seconds):
    lbl1.config(bg='yellow')
    lbl1.config(height=3, font=('times', 20, 'bold'))
    for k in range(seconds, 0, -1):
        lbl1["text"] = k
        root.update()
        time.sleep(1)
    lbl1.config(bg='red')
    lbl1.config(fg='white')
    lbl1["text"] = "Time up!"
    tkMessageBox.showinfo("Time up!","Time up!")

def GetSource():
    get_window = Tkinter.Toplevel(root)
    get_window.title('Source File?')
    Tkinter.Entry(get_window, width=30,
                  textvariable=source).pack()
    Tkinter.Button(get_window, text="Change",
                   command=lambda: update_specs()).pack()


root = Tk()
root.title("Countdown")
lbl1 = Label()
lbl1.pack(fill=BOTH, expand=1)
app = App(root)
root.mainloop()</pre>