python-在Tkinter中单击后禁用按钮

def appear(x):
    return lambda: results.insert(END, x)

letters=["A", "T", "D", "M", "E", "A", "S", "R", "M"] 

for index in range(9): 
    n=letters[index] 
    nButton = Button(buttons, bg="White", text=n, width=5, height=1,
    command =appear(n), relief=GROOVE).grid(padx=2, pady=2, row=index%3,
    column=index/3)

我要尝试的是单击按钮后将其禁用.
我试过了

def appear(x):
    nButton.config(state="disabled")
    return lambda: results.insert(END, x)

但这给了我以下错误：

NameError: global name ‘nButton’ is not defined

>每当动态创建窗口小部件时,都需要将对它们的引用存储在集合中,以便以后可以访问它们.
> Tkinter小部件的网格方法始终返回None.因此,您需要将对网格的任何调用放在自己的线路上.
>每当将按钮的命令选项分配给需要自变量的函数时,都必须使用lambda或此类命令来“隐藏”该函数的调用,直到单击按钮为止.有关更多信息,请参见https://stackoverflow.com/a/20556892/2555451.

以下是解决所有这些问题的示例脚本：

from Tkinter import Tk, Button, GROOVE

root = Tk()

def appear(index, letter):
    # This line would be where you insert the letter in the textbox
    print letter

    # Disable the button by index
    buttons[index].config(state="disabled")

letters=["A", "T", "D", "M", "E", "A", "S", "R", "M"]

# A collection (list) to hold the references to the buttons created below
buttons = []

for index in range(9): 
    n=letters[index]

    button = Button(root, bg="White", text=n, width=5, height=1, relief=GROOVE,
                    command=lambda index=index, n=n: appear(index, n))

    # Add the button to the window
    button.grid(padx=2, pady=2, row=index%3, column=index/3)

    # Add a reference to the button to 'buttons'
    buttons.append(button)

root.mainloop()