当我在 tkinter 中按下开始和暂停按钮几次时，倒数计时器的速度会增加

Question

我有一个倒计时脚本，当我一次又一次按下开始和暂停按钮几次时，秒数会快速更新。

起初我认为在开始和暂停按钮之间快速单击会加快秒数，因此我添加了time.sleep(1) 以延迟在不起作用的按钮之间单击。

我该如何解决这个问题？

我的算法正确吗？或者还有其他更好的方法来进行倒计时吗？如果是，我该怎么做？

代码

from tkinter import *

PAUSE = False
HOUR, MINUTE, SECOND = 0, 0, 0


def start():
    '''Command for START button'''

    global PAUSE

    PAUSE = False
    start_button['state'] = 'disabled'
    pause_button['state'] = 'normal'
    reset_button['state'] = 'normal'
    # time.sleep(1) to delay time between clicks of pause and start buttons
    Counter()


def pause():
    '''Command for PAUSE button'''

    global PAUSE

    PAUSE = True
    start_button['state'] = 'normal'
    pause_button['state'] = 'disabled'


def reset():
    '''Command for RESET button'''

    global HOUR, MINUTE, SECOND, PAUSE

    PAUSE = True
    start_button['state'] = 'normal'
    pause_button['state'] = 'disabled'
    reset_button['state'] = 'disabled'
    Time['text'] = '00:00:00'

    HOUR, MINUTE, SECOND = 0, 0, 0


def Counter():
    '''Updating hour, minute and seconds'''

    global HOUR, MINUTE, SECOND

    if PAUSE is False:
        if SECOND == 59:
            if MINUTE == SECOND == 59:
                HOUR += 1

            if MINUTE == 59:
                MINUTE = 0

            else:
                MINUTE += 1

            SECOND = -1

        SECOND += 1

        Time.config(text='{}:{}:{}'.format(str(HOUR).zfill(2), str(MINUTE).zfill(2), str(SECOND).zfill(2)))
        root.after(1000, Counter)


root = Tk()
root.title('COUNTER')

width, height = 342, 108
pos_x = root.winfo_screenwidth() // 2 - width // 2
pos_y = root.winfo_screenheight() // 2 - height // 2

root.geometry('{}x{}+{}+{}'.format(width, height, pos_x, pos_y))

Time = Label(root, fg='Black', text='00:00:00', font=("Helvetica", 40))
Time.pack(side='bottom')

start_button = Button(root, text='START', font=("Arial", 16), fg='black', width=8, command=start)
start_button.pack(side='left')

pause_button = Button(root, text='PAUSE', font=("Arial", 16), fg='black', width=8, state='disabled', command=pause)
pause_button.pack(side='left')

reset_button = Button(root, text='RESET', font=("Arial", 16), fg='black', width=10, state='disabled', command=reset)
reset_button.pack(side='left', fill='both')

root.mainloop()

Answer 1

起初我认为在开始和暂停按钮之间快速单击会加快秒数，因此我添加了 time.sleep(1) 以延迟在不起作用的按钮之间单击。

问题在于，由于.aftert() 方法回调自身之前存在延迟，因此多次点击开始按钮并创建.after(1000, counter) 的多个循环。这意味着有许多.after() 循环同时发生。要解决这个问题，您只需要这样做，如果有 .after() 循环，则无法按下开始按钮。

为此，您必须更改三个函数

counter() 函数

我已经更改了代码，所以如果计数器正在运行，那么start_button 将被禁用，当计数器停止运行时，其状态将恢复正常

def Counter():
    '''Updating hour, minute and seconds'''
    global HOUR, MINUTE, SECOND

    if PAUSE is False:
        start_button['state'] = 'disabled' # setting it to disabled if the counter is running
        if SECOND == 59:
            if MINUTE == SECOND == 59:
                HOUR += 1

            if MINUTE == 59:
                MINUTE = 0

            else:
                MINUTE += 1

            SECOND = -1

        SECOND += 1

        Time.config(text='{}:{}:{}'.format(str(HOUR).zfill(2), str(MINUTE).zfill(2), str(SECOND).zfill(2)))
        root.after(1000, Counter)
    else:
        start_button['state'] = 'normal' # setting it to normal if the counter stops

pause() 和 reset() 函数

您必须取消将start_button 的状态设置为正常的功能，因为这将允许在最后一个计数器循环完成之前按下start_button

def pause():
    '''Command for PAUSE button'''

    global PAUSE

    PAUSE = True
    pause_button['state'] = 'disabled'

def reset():
    '''Command for RESET button'''

    global HOUR, MINUTE, SECOND, PAUSE

    PAUSE = True
    pause_button['state'] = 'disabled'
    reset_button['state'] = 'disabled'
    Time['text'] = '00:00:00'

    HOUR, MINUTE, SECOND = 0, 0, 0

更新这些功能将消除此错误。 希望这是您正在寻找的答案:)

Answer 2

您的Counter 函数每次单击都会调用root.after(1000,Counter)，并且还会在单击时立即修改Time 标签。当您足够快地单击按钮时，您可以安排多个 root.after 并添加秒数。

要修改当前脚本，您可以跟踪当前操作，并调用root.after_cancel 暂停操作。

from tkinter import *

PAUSE = False
HOUR, MINUTE, SECOND = 0, 0, 0
action = None #keep track on current action and also avoid click spam


def start():
    '''Command for START button'''

    global PAUSE, action

    PAUSE = False
    ...
    if not action:
        Counter()


def pause():
    '''Command for PAUSE button'''

    global PAUSE, action

    ...
    if action:
        root.after_cancel(action)
        action = None


def reset():
    '''Command for RESET button'''

    global HOUR, MINUTE, SECOND, PAUSE, action

    ...

    HOUR, MINUTE, SECOND = 0, 0, 0
    action = None


def Counter():
    '''Updating hour, minute and seconds'''

    global HOUR, MINUTE, SECOND, action

    if PAUSE is False:
        if SECOND == 59:
            if MINUTE == SECOND == 59:
                HOUR += 1

            if MINUTE == 59:
                MINUTE = 0

            else:
                MINUTE += 1

            SECOND = -1

        SECOND += 1

        Time.config(text='{}:{}:{}'.format(str(HOUR).zfill(2), str(MINUTE).zfill(2), str(SECOND).zfill(2)))
        action = root.after(1000, Counter)

root = Tk()
...
start_button = Button(root, text='START', font=("Arial", 16), fg='black', width=8, command=lambda: root.after(1000,start)) #to avoid the instant second increment