tkinter 中 while 循环的替代方案

Question

我正在尝试制作一个闹钟应用程序：闹钟应该在预设的时间响起。如果没有 tkinter，我的代码完全可以正常工作，但是使用 tkinter 它根本不起作用。 在原始代码中有一个 while 循环，我注意到并读到它不能与 tkinter 结合使用。我决定摆脱循环，但现在当我输入时间时警报会立即响起。

我已经阅读了有关使用 r.after(time_ms, function()) 的信息。但我不知道如何在我的代码中正确实现它。我读过它必须在函数的末尾和 r.mainloop() 之前，但我无法让它工作。有人能帮帮我吗？非常感谢你！ 我已经阅读了很多关于此的或 stackoverflow 帖子，但我没有足够的经验来让它与这些答案一起工作。 :(

import tkinter as tk
from datetime import datetime, date
import time
from pygame import mixer

r = tk.Tk()
r.title('Smart Watch')

def alarm_sound():
    mixer.init()
    mixer.music.load('Wecker-sound.mp3')

def end():
    mixer.init()
    mixer.music.stop()

def display_output():
    hour = entry_hour.get()
    int_hour = int(hour)
    minute = entry_minute.get()
    int_minute = int(minute)
    second = entry_second.get()
    int_second = int(second)
    confirmation_message = ('Alarm has been set for ' + hour + ':' +
                             minute + ':' + second + '.')
    text_label['text'] = confirmation_message


    if (time.localtime().tm_hour == hour and
            time.localtime().tm_min == entry_minute.get() and
                time.localtime().tm_sec == entry_second.get()):
        alarm_sound()
        mixer.music.play()

message = tk.Label(r, text='What is the alarm message you\'d like to receive when the alarm goes off?',
                  font=('Roboto-regular', 12), fg='black')
message.pack()
entry_message = tk.Entry(r, width=45)
entry_message.pack()
enter_hour = tk.Label(r, text='Enter the hour for the alarm to go off: ',
                        font=('Roboto-regular', 12), fg='black')
enter_hour.pack()
entry_hour = tk.Entry(r, width=10)
entry_hour.pack()
enter_minute = tk.Label(r, text='Enter the minute for the alarm to go off: ',
                        font=('Roboto-regular', 12), fg='black')
enter_minute.pack()
entry_minute = tk.Entry(r, width=10)
entry_minute.pack()
enter_second = tk.Label(r, text='Enter the second for the alarm to go off: ',
                    font=('Roboto-regular', 12), fg='black')
enter_second.pack()
entry_second = tk.Entry(r, width=10)
entry_second.pack()
text_label = tk.Label(r, font=('Roboto-regular', 12, 'bold'),
                      fg='tomato')
text_label.pack()
submit_button = tk.Button(r, text='Submit',
                          fg='black', width=30, height=2, relief='groove',
                          cursor='hand2', command=display_output)
submit_button.pack()
snooze_button = tk.Button(r, text='Snooze alarm',
                          fg='black',
                          width=30, height=2, relief='groove',
                          cursor='hand2', command=end)
snooze_button.pack()


r.mainloop()

# The original code without tkinter has the while loop like this:
while True:
    if time.localtime().tm_hour == hr and time.localtime().tm_min == mn and time.localtime().tm_sec == sc:
        print(message)
        break
alarm_Sound()
mixer.music.play()

Answer 1

首先，您应该使用全局变量来保留来自Entry 的值，然后在检查时间的函数中使用它们。此函数应在没有时间报警时使用after 再次运行。它还应该跳过after() 以停止检查时间。

def display_output():
    global int_hour
    global int_minute
    global int_second

    hour = entry_hour.get()
    int_hour = int(hour)

    minute = entry_minute.get()
    int_minute = int(minute)

    second = entry_second.get()
    int_second = int(second)

    text_label['text'] = 'Alarm has been set for {}:{}:{}.'.format(hour, minute, second)
    # start checking time    
    check_time()


def check_time():

    dt = time.localtime()

    if (dt.tm_hour == int_hour and dt.tm_min == int_minute and dt.tm_sec == int_second):
        alarm_sound()
        mixer.music.play()
    else:
        r.after(1000, check_time) # check it again after 1000ms but only if it doesn't play sound

---

代码需要其他全局变量来控制警报是否在您停止和尝试再次设置时运行。

---

import time
from datetime import datetime, date
import tkinter as tk
from pygame import mixer

# --- functions ---

def alarm_sound():
    global running_alarm

    running_alarm = True

    mixer.music.load('Wecker-sound.mp3')

def end():
    global running_alarm

    if running_alarm:
        running_alarm = False
        mixer.music.stop()
        text_label['text'] = ''

def display_output():
    global int_hour
    global int_minute
    global int_second

    hour = entry_hour.get()
    int_hour = int(hour)

    minute = entry_minute.get()
    int_minute = int(minute)

    second = entry_second.get()
    int_second = int(second)

    confirmation_message = ('Alarm has been set for {}:{}:{}.'.format(hour, minute, second))

    text_label['text'] = confirmation_message

    check_time()


def check_time():

    dt = time.localtime()

    if (dt.tm_hour == int_hour and dt.tm_min == int_minute and dt.tm_sec == int_second):
        checking_time = False # stop l
        alarm_sound()
        mixer.music.play()
    else:
        r.after(1000, check_time)

# --- main ---

running_alarm = False # default value at start

mixer.init()


r = tk.Tk()
r.title('Smart Watch')

message = tk.Label(r, text='What is the alarm message you\'d like to receive when the alarm goes off?',
                  font=('Roboto-regular', 12), fg='black')
message.pack()

entry_message = tk.Entry(r, width=45)
entry_message.pack()

enter_hour = tk.Label(r, text='Enter the hour for the alarm to go off: ',
                        font=('Roboto-regular', 12), fg='black')
enter_hour.pack()

entry_hour = tk.Entry(r, width=10)
entry_hour.pack()

enter_minute = tk.Label(r, text='Enter the minute for the alarm to go off: ',
                        font=('Roboto-regular', 12), fg='black')
enter_minute.pack()

entry_minute = tk.Entry(r, width=10)
entry_minute.pack()

enter_second = tk.Label(r, text='Enter the second for the alarm to go off: ',
                    font=('Roboto-regular', 12), fg='black')
enter_second.pack()

entry_second = tk.Entry(r, width=10)
entry_second.pack()

text_label = tk.Label(r, font=('Roboto-regular', 12, 'bold'),  fg='tomato')
text_label.pack()

submit_button = tk.Button(r, text='Submit',
                          fg='black', width=30, height=2, relief='groove',
                          cursor='hand2', command=display_output)
submit_button.pack()

snooze_button = tk.Button(r, text='Snooze alarm',
                          fg='black',
                          width=30, height=2, relief='groove',
                          cursor='hand2', command=end)
snooze_button.pack()

r.mainloop()

Answer 2

代替while True: 循环，使用一个函数并在每个“指定间隔”时间为该函数注册一个回调。这是在下面的代码中完成的：

def wait_for_alarm():
    after = r.after(1000, wait_for_alarm)  # 1000 refers to 1 second
    if time.localtime().tm_hour == hr and time.localtime().tm_min == mn and time.localtime().tm_sec == sc:
        print(message)
        alarm_Sound()
        mixer.music.play()