Question

如何保存设置闹钟时返回的闹钟的引用，然后取消闹钟？我需要一个停止功能，以便用户可以结束程序。

p = ' IDKMYBFFJILL!'
k = 0

def new_char():
    global k
    label.config(text=p[k])
    k = (k+1)%len(p)
    window.after(500,new_char)

def end():
    window.after.cancel(new_char)

from Tkinter import *

window=Tk()
window.title('New char program')

label = Label(window,text='',width=2,font=('Times New Roman',200))
label.grid()

begin_button = Button(window,text='begin',command=new_char)
begin_button.grid(row=1,column=1,sticky='EW')

end_button = Button(window,text='end',command=end)
end_button.grid(row=1,column=2,sticky='EW')

window.mainloop()

Answer 1

您必须捕获alarm()的输出，这是一个“警报标识符”，然后您可以将其传递给alarm_cancel()，即alarm_cancel(<alarm_identifier>)。（注意：语法为alarm_cancel()，带有下划线 - 而非alarm.cancel()，就像您尝试的那样）

执行此操作的一种方法是将警报功能封装在一个类中，我称之为Alarm：

from Tkinter import *

p = ' IDKMYBFFJILL!'
k = 0

# Create Alarm class
class Alarm(object):
    def __init__(self):
        self.alarm_id = None

    def new_char(self):
        global k
        label.config(text=p[k])
        k = (k+1)%len(p)
        self.alarm_id = window.after(500,self.new_char)

    def end(self):
        window.after_cancel(self.alarm_id)

# Create Alarm instance (called alarm)
alarm = Alarm()

window=Tk()
window.title('New char program')

label = Label(window,text='',width=2,font=('Times New Roman',200))
label.grid()

begin_button = Button(window,text='begin',command=alarm.new_char)  # Note change
begin_button.grid(row=1,column=1,sticky='EW')

end_button = Button(window,text='end',command=alarm.end)           # Note change
end_button.grid(row=1,column=2,sticky='EW')

window.mainloop()

您可以更进一步，将p和k移到Alarm类中，无需global - 但无需解决问题。

Answer 2

您可以设置停止标志，以指示何时停止以及循环停止后要执行的操作：

from Tkinter import *


p = ' IDKMYBFFJILL!'
k = 0

stop_loop = False # the stop flag set when cancel is pressed

def new_char():
    global k

    if stop_loop: # execute this when you press cancel
        print("K value when cancel was stopped: ", k)
        return

    label.config(text=p[k])
    k = (k+1)%len(p)
    window.after(500,new_char)

def end():
    global stop_loop
    stop_loop = True # set the flag that you want to stop (done when pressed cancel button)

编写一个函数来结束程序？

2 个答案: