tkinter：如何在同一处理程序中的小部件更改之间插入延迟？

大约两年前，当我试图在Tkinter画布上模拟LED时，我问了一个类似的问题。然后，解决方案是使用canvas after（）方法而不是sleep（）函数在小部件更新之间引入延迟

从那以后，我发现了tk_工具模块，它有一个内置的功能来创建LED，太棒了！但我现在遇到了和以前一样的问题，那就是：每个LED的开启（变为绿色）之间如何有1秒的延迟

当运行下面的代码时，实际发生的情况是LED显示在关闭状态（灰色），然后当我单击“开始”按钮时，会有4秒钟的延迟，之后所有LED同时打开

多谢各位。 约翰尼姆

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我猜每当回调函数完成执行时，所有的LED都会同时亮起。因此，我决定创建一个线程，并使用

after（）

停止时间（

sleep（）

停止主线程，使其持续4秒）

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最好避免停止应用程序的睡眠，并在之后使用

。将调用链接到after回调，以便每个调用下一个，或在每个led的循环中调用它们，但延迟1、2、3、4秒

链接版本：

# LED array simulation

from tkinter import *
import tk_tools as tkt

# list to hold a 4-LED array
led_array = []

# GUI
root = Tk()

# create 4 LED widgets, store them in led_array[], display them
for i in range(4):
    led_array.append(tkt.Led(root, size=30))
    led_array[i].grid(row=0, column=i)

# Both answers are common to here.

def on_after( led_list ):
    led_list[0].to_green() # Set first item in the list.
    if len( led_list ) > 1:
        # Call on_after again with a shortened list.
        root.after( 1000, on_after, led_list[1:] )
    else:
        # Enable the start button
        start.config( state = NORMAL )

# turn on LEDs (change to green) with a 1-second delay between each
def turn_on():
    start.config( state = DISABLED ) # Disable the button
    root.after( 1000, on_after, led_array)

# create button to initiate LED turn-on sequence
start = Button(root, text='Start', padx=20, command=turn_on)
start.grid(row=1, columnspan=4)

root.mainloop()

# Both answers are common to here.
def on_after( led ):
    led.to_green()

def enable():
    start.config( state = NORMAL )

# turn on LEDs (change to green) with a 1-second delay between each
def turn_on():
    start.config( state = DISABLED ) # Disable the button
    for ix, led in enumerate( led_array ):
        # Call on_after 4 times with 1 to 4 second delays
        root.after( 1000 * (1+ix), on_after, led )
    root.after( 1000*(ix+1), enable )

# create button to initiate LED turn-on sequence
start = Button(root, text='Start', padx=20, command=turn_on)
start.grid(row=1, columnspan=4)

root.mainloop()

循环版本：

# LED array simulation

from tkinter import *
import tk_tools as tkt

# list to hold a 4-LED array
led_array = []

# GUI
root = Tk()

# create 4 LED widgets, store them in led_array[], display them
for i in range(4):
    led_array.append(tkt.Led(root, size=30))
    led_array[i].grid(row=0, column=i)

# Both answers are common to here.

def on_after( led_list ):
    led_list[0].to_green() # Set first item in the list.
    if len( led_list ) > 1:
        # Call on_after again with a shortened list.
        root.after( 1000, on_after, led_list[1:] )
    else:
        # Enable the start button
        start.config( state = NORMAL )

# turn on LEDs (change to green) with a 1-second delay between each
def turn_on():
    start.config( state = DISABLED ) # Disable the button
    root.after( 1000, on_after, led_array)

# create button to initiate LED turn-on sequence
start = Button(root, text='Start', padx=20, command=turn_on)
start.grid(row=1, columnspan=4)

root.mainloop()

# Both answers are common to here.
def on_after( led ):
    led.to_green()

def enable():
    start.config( state = NORMAL )

# turn on LEDs (change to green) with a 1-second delay between each
def turn_on():
    start.config( state = DISABLED ) # Disable the button
    for ix, led in enumerate( led_array ):
        # Call on_after 4 times with 1 to 4 second delays
        root.after( 1000 * (1+ix), on_after, led )
    root.after( 1000*(ix+1), enable )

# create button to initiate LED turn-on sequence
start = Button(root, text='Start', padx=20, command=turn_on)
start.grid(row=1, columnspan=4)

root.mainloop()

我可能会使用链式版本，尽管在这种情况下，循环式版本可能更容易理解。
很抱歉，我不熟悉OOP，因此我无法真正理解这个答案。我一直在寻找一种方法来解决这个问题，我使用的范例就是函数式编程。