如何檢查tkinter中是否存在按鈕？

Question

所以我正在製作一個Tic-Tac-Toe程序，因爲我很無聊。我正在使用tkinter，並且我有一個程序詢問你想要的是哪一邊，然後一個窗口彈出9個按鈕。當按下其中一個按鈕時，出現一個圖像X或O。然後該按鈕被刪除。現在我正在製作程序的CPU移動部分。當按下按鈕（和刪除）時，它將會有一個循環。一旦隨機按鈕被調用，循環將被打破。我的困境是：我不知道如何檢查按鈕是否存在，或者循環應該是什麼樣子。下面是代碼：

from tkinter import * 
import sys 
import time 
import random 

tk = Tk() 

xoro = input("Choose a side, X or O.") 
if xoro == "x": 
    side = 0 
elif xoro == "o": 
    side = 1 
else: 
    print("Please enter x or o.") 

canvas = Canvas(tk, width=498, height=498, background="green") 
canvas.pack() 
tk.title("Tic-Tac-Toe!") 
time.sleep(2) 

photo2 = PhotoImage(file="C:\Python34\X.gif") 
photo1 = PhotoImage(file="C:\Python34\O.gif") 
photolist = [photo2, photo1] 

def PlaceImage(photo, x, y, buttontodelete): 
    canvas.create_image(x,y, image=photo) 
    buttontodelete.destroy() 

button1 = Button(tk, text="Choose Me!") 
button1 = Button(tk, text="Choose Me!", bg="green", command=lambda: PlaceImage(photolist[side], 75, 75, button1)) 
button1.pack() 
button1.place(bordermode=OUTSIDE, height=166, width=166) 
button1.place(x=0, y=0) 
button1.config(highlightbackground="black") 

button2 = Button(tk, text="Choose Me!") 
button2 = Button(tk, text="Choose Me!", bg="green", command=lambda: PlaceImage(photolist[side], 75, 241, button2)) 
button2.pack() 
button2.place(bordermode=OUTSIDE, height=166, width=166) 
button2.place(x=0, y=166) 
button2.config(highlightbackground="black") 

button3 = Button(tk, text="Choose Me!") 
button3 = Button(tk, text="Choose Me!", bg="green", command=lambda: PlaceImage(photolist[side], 75, 407, button3)) 
button3.pack() 
button3.place(bordermode=OUTSIDE, height=166, width=166) 
button3.place(x=0, y=332) 
button3.config(highlightbackground="black") 

button4 = Button(tk, text="Choose Me!") 
button4 = Button(tk, text="Choose Me!", bg="green", command=lambda: PlaceImage(photolist[side], 241, 75, button4)) 
button4.pack() 
button4.place(bordermode=OUTSIDE, height=166, width=166) 
button4.place(x=166, y=0) 
button4.config(highlightbackground="black") 

button5 = Button(tk, text="Choose Me!") 
button5 = Button(tk, text="Choose Me!", bg="green", command=lambda: PlaceImage(photolist[side], 241, 241, button5)) 
button5.pack() 
button5.place(bordermode=OUTSIDE, height=166, width=166) 
button5.place(x=166, y=166) 
button5.config(highlightbackground="black") 

button6 = Button(tk, text="Choose Me!") 
button6 = Button(tk, text="Choose Me!", bg="green", command=lambda: PlaceImage(photolist[side], 241, 407, button6)) 
button6.pack() 
button6.place(bordermode=OUTSIDE, height=166, width=166) 
button6.place(x=166, y=332) 
button6.config(highlightbackground="black") 

button7 = Button(tk, text="Choose Me!") 
button7 = Button(tk, text="Choose Me!", bg="green", command=lambda: PlaceImage(photolist[side], 407, 75, button7)) 
button7.pack() 
button7.place(bordermode=OUTSIDE, height=166, width=166) 
button7.place(x=332, y=0) 
button7.config(highlightbackground="black") 

button8 = Button(tk, text="Choose Me!") 
button8 = Button(tk, text="Choose Me!", bg="green", command=lambda: PlaceImage(photolist[side], 407, 241, button8)) 
button8.pack() 
button8.place(bordermode=OUTSIDE, height=166, width=166) 
button8.place(x=332, y=166) 
button8.config(highlightbackground="black") 

button9 = Button(tk, text="Choose Me!") 
button9 = Button(tk, text="Choose Me!", bg="green", command=lambda: PlaceImage(photolist[side], 407, 407, button9)) 
button9.pack() 
button9.place(bordermode=OUTSIDE, height=166, width=166) 
button9.place(x=332, y=332) 
button9.config(highlightbackground="black") 

buttonlist = [button1, button2, button3, button4, button5, button6, button7, button8, button9] 
randombutton = random.randint(0, 8) 
WHILE BLAH IS TRUE: 
    buttonlist[randombutton].invoke() 
    BREAK OUT OF LOOP, AND BEGIN USER'S TURN 

mainloop() 

Answer 1

而不是刪除按鈕，只需將其隱藏（與.pack_forget()方法），並檢查按鈕的可見性（。可見，我認爲.winfo_viewable()方法）。

Answer 2

.winfo_exists()方法測試小部件的存在。

>>> from tkinter import * 
>>> app = Tk() 
>>> b = Button(text="hello") 
>>> b.winfo_exists() 
1 
>>> b.destroy() 
>>> b.winfo_exists() 
0 

儘量避免循環。您需要引發事件並允許事件循環儘可能多地運行。在Tk中，.event_generate()方法或.after()調度程序方法對此很有用。