如何停止列印機功能？

    from tkinter import *
    
    root = Tk()
    
    #This function should stop the function printer
    def button_status(is_clicked):
        return is_clicked
    
    #This function prints integer numbers from 0 to 2
    def printer():
        for i in range(3):
            print(i)
            if(button_status==True):
                break
                
    button = Button(root, text="Stampa",height=2, width=6, command= printer, font=("TkDefaultFont",18),bg='white')
    button.place(x=630, y=680)    
    button3 = Button(root, text="Termina",height=2, width=6, command= lambda: button_status(True), font=("TkDefaultFont",18),bg='white')
    button3.place(x=780, y=680)
    
    print(button_status)
    root.state('zoomed')
    root.mainloop()

uj5u.com熱心網友回復：

您需要在代碼中更改一些內容，以允許一個函式控制另一個函式的行為。

需要更改的第一件事是不需要printer使用 Python 回圈。如果這樣做，tkinter將沒有機會運行任何其他代碼，因為它將首先等待printer函式回傳。相反，讓printer第一次呼叫的按鈕傳入一個數字，并讓 tkinter 主回圈在短暫延遲后再次呼叫該函式本身。

def printer(i):
    print(i)                            # Note, this always prints at least once. Move the
    if i < 2 and not button_status:     # print call inside the `if` if you don't want that.
        root.after(1000, printer, i 1)  # Schedule ourselves to be called again in one second

button = Button(root, text="Stampa",height=2, width=6, command=lambda: printer(0),
                font=("TkDefaultFont",18),bg='white')
button.place(x=630, y=680)    

您需要更改的另一件事是在兩個函式之間共享狀態的某種方式。最簡單的方法是使用全域變數，但您可能會考慮將兩個函式重新設計為類的方法，以便它們可以通過實體變數共享狀態。這是全域變數設定的樣子（printer上面已經可以使用此代碼）：

button_status = False     # Set an initial value

def stop_counting():
    global button_status  # This tells Python we want to be able to change the global variable
    button_status = True  # Use `button_status = not button_status` if you want it to toggle

button3 = Button(root, text="Termina",height=2, width=6, command=stop_counting,
                 font=("TkDefaultFont",18),bg='white')
button3.place(x=780, y=680)

uj5u.com熱心網友回復：

停止列印輸出的另一種方法是使用標志布林值。

此方法將標志存盤在串列中，從而避免在函式中使用全域陳述句。

import tkinter as tk

root = tk.Tk()

# termination flag in list
termina = [ False ]

#This function should stop the function printer
def button_status():
    termina[ 0 ] = True

#This function prints integer numbers from 0 to 2999
def printer():
    # Setup termination flag for printing
    termina[ 0 ] = False
    for i in range(3000):
        root.update()
        if termina[ 0 ]: # test for True status
            break
        else:
            print(i)
            
buttonA = tk.Button(
    root, text="Stampa", command= printer,
    font=("TkDefaultFont",18), bg='white')
buttonA.grid(sticky = tk.NSEW)

buttonB = tk.Button(
    root, text="Termina", command= button_status,
    font=("TkDefaultFont",18), bg='white')
buttonB.grid(sticky = tk.NSEW)

# root.state('zoomed')
root.mainloop()

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