python - 如何使倒计时显示在 tkinter 窗口而不是我的 cmd 中？

Question

这段代码基本上允许用户设置倒计时(以秒为单位)，当倒计时归零时会出现一条消息。我是 tkinter 和 python 的初学者，所以我不知道如何让我的倒计时显示在 tkinter 窗口中，因为它只显示在 cmd 中。

import time
import tkinter as Alarm
class test(Alarm.Frame):
    def __init__(self, parent):
        Alarm.Frame.__init__(self, parent)
        self.prompt = Alarm.Label(self, text="Enter seconds:", anchor="w")
        self.entry = Alarm.Entry(self)
        self.output = Alarm.Label(self, text="")
        self.submit = Alarm.Button(self, text="Submit", command = self.startTimer)
        self.prompt.pack(side="top", fill="x")
        self.entry.pack(side="top", fill="x", padx=20)
        self.output.pack(side="top", fill="x", expand=True)
        self.submit.pack(side="right")
    def countdown(k,q):
        j=q
        k=0
        while True:
            if(j>=0):
                print(str(j),end="\r")
            time.sleep(1)
            j-=1
            if(j==-1):
                break
        if(j==-1):
            print("Alarm!", end="\r")
            time.sleep(1)
    def startTimer(self):
        try:
            i = int(self.entry.get())
            self.countdown(i)
        except ValueError:
            print("Please enter whole digits only in all boxes")
if __name__ == "__main__":
    root = Alarm.Tk()
    test(root).pack(fill="both", expand=True)
    root.mainloop()

Answer 1

如果你想显示一些动画，after() 是可行的方法。不要使用 time.sleep()，因为它会卡住您的 mainloop。

import tkinter as Alarm

class test(Alarm.Frame):
    def __init__(self, parent):
        Alarm.Frame.__init__(self, parent)
        self.prompt = Alarm.Label(self, text="Enter seconds:", anchor="w")
        self.entry = Alarm.Entry(self)
        self.output = Alarm.Label(self, text="Start")
        self.submit = Alarm.Button(self, text="Submit", command = self.startTimer)
        self.prompt.pack(side="top", fill="x")
        self.entry.pack(side="top", fill="x", padx=20)
        self.output.pack(side="top", fill="x", expand=True)
        self.submit.pack(side="right")

    def countdown(self, s):
        if s==0:
            self.output.configure(text="Alarm!")
            return  
        self.output.configure(text=str(s))
        s -= 1
        self.output.after(1000, lambda: self.countdown(s))

    def startTimer(self):
        try:
            i = int(self.entry.get())
            self.countdown(i)
        except ValueError:
            print("Please enter whole digits only in all boxes")

if __name__ == "__main__":
    root = Alarm.Tk()
    test(root).pack(fill="both", expand=True)
    root.mainloop()