按下按钮时如何停止文本标签的闪烁？

Question

I am created two button and two text label and my application is when "1" is pressed "hello" should start blinking and when "2" is pressed "hi" should start blinking and "hello" should stop blinking.it is a demo code of my main project . Here is my code.

import tkinter as Tk
flash_delay = 500  # msec between colour change
flash_colours = ('white', 'red') # Two colours to swap between

def flashColour(object, colour_index):
    object.config(background = flash_colours[colour_index])
    root.after(flash_delay, flashColour, object, 1 - colour_index)
def flashColour1(object, colour_index):
    root.txt.config(bg="white")
    object.config(background=flash_colours[colour_index])
    root.after(flash_delay, flashColour1, object, 1 - colour_index)
root = Tk.Tk()
root.geometry("100x100")
root.txt = Tk.Text(root, height=2,width=10,font=("TimesNewroman",7,'bold'),
                   background = flash_colours[0])
root.txt.pack()
root.txt.insert(Tk.END,"hello")
root.txt1 = Tk.Text(root, height=2,width=10,font=("TimesNewroman",7,'bold'),
                   background = flash_colours[0])
root.txt1.pack()
root.txt1.insert(Tk.END,"hi")

root.button1=Tk.Button(root,text="1",command = lambda: flashColour(root.txt, 0))
root.button1.pack()
root.button2=Tk.Button(root,text="2",command = lambda: flashColour1(root.txt1, 0))
root.button2.pack()
root.mainloop()

Answer 1

Try this... It will work

import tkinter as Tk

flash_delay = 500  # msec between colour change
flash_colours = ('white', 'red')  # Two colours to swap between


def flashColour(object, colour_index):
    global a
    object.config(background=flash_colours[colour_index])
    a = root.after(flash_delay, flashColour, object, 1 - colour_index)


def flashColour1(object, colour_index):
    global b
    root.txt.config(bg="white")
    object.config(background=flash_colours[colour_index])
    b = root.after(flash_delay, flashColour1, object, 1 - colour_index)


def stopFlash(object, colour_index):
    root.txt.config(bg="white")
    object.config(background=flash_colours[colour_index])
    root.after_cancel(a)


def stopFlash1(object, colour_index):
    root.txt.config(bg="white")
    object.config(background=flash_colours[colour_index])
    root.after_cancel(b)


root = Tk.Tk()
root.geometry("100x160")
root.txt = Tk.Text(root, height=2, width=10, font=("TimesNewroman", 7, 'bold'),
                   background=flash_colours[0])
root.txt.pack()
root.txt.insert(Tk.END, "hello")
root.txt1 = Tk.Text(root, height=2, width=10, font=("TimesNewroman", 7, 'bold'),
                    background=flash_colours[0])
root.txt1.pack()
root.txt1.insert(Tk.END, "hi")

root.button1 = Tk.Button(root, text="1", command=lambda: flashColour(root.txt, 0))
root.button1.pack()
root.button2 = Tk.Button(root, text="2", command=lambda: flashColour1(root.txt1, 0))
root.button2.pack()
root.button3 = Tk.Button(root, text="Stop1", command=lambda: stopFlash(root.txt, 0))
root.button3.pack()
root.button4 = Tk.Button(root, text="Stop2", command=lambda: stopFlash1(root.txt1, 0))
root.button4.pack()
root.mainloop()

Used root.after_cancel(after_id) to cancel the effect of after !

Answer 2

Just save the ID of the after(...) task and use after_cancel(...) to cancel the scheduled task:

def flashColour(object, colour_index):
    object.config(background = flash_colours[colour_index])
    flashColour.after_id = root.after(flash_delay, flashColour, object, 1 - colour_index)

def flashColour1(object, colour_index):
    if hasattr(flashColour, 'after_id'):
        root.after_cancel(flashColour.after_id)
    root.txt.config(bg="white")
    object.config(background=flash_colours[colour_index])
    root.after(flash_delay, flashColour1, object, 1 - colour_index)