如何设置Tkinter按钮以单击一次即可擦除？

Question

As the title says, I want to erase a button when it is clicked. I have tried many different styles and this one seemed to be the simplest, but I keep getting the error:

line 34, in incorrect
    button2.Button.destroy()
NameError: name 'button2' is not defined

and when trying a different method as shown below, this one:

NameError: name 'button2' is not defined

When trying to define it in the beginning I would receive this error:

UnboundLocalError: local variable 'button2' referenced before assignment

Any help would be greatly appreciated, thank you.

My code:

from tkinter import *

class Application(object):
     def __init__(self):
          self.root = Tk()
          self.root.configure(bg="darkorchid1", padx=10, pady=10)
          self.root.title("WELCOME TO THIS PROGRAM)")

    self.username = "Bob"

    program = Label(self.root, text="MY PROGRAM", bg="lightgrey", fg="darkorchid1")
    program.pack()

    label0 = Label(self.root, text="ENTER USERNAME:", bg="purple", fg="white", height=5, width=50)
    label0.pack()

    self.entry = Entry(self.root, width=25)
    self.entry.configure(fg= "white",bg="grey20")
    self.entry.pack()

    button = Button(self.root, text="SUBMIT", highlightbackground="green", width=48, command=self.correct)
    button.pack()

def correct(self):
    username = self.entry.get()
    if username == self.username:
        button1 = Button(self.root, text='LOGIN', highlightbackground="green", width=28, command=self.root.destroy)
        button1.pack()
    elif username != self.username:
       button2 = Button(self.root, text="INCORRECT- CLICK TO DIMISS THIS MESSAGE", highlightbackground="red", width=48, command=self.incorrect)
       button2.pack()

def incorrect(self):
    button2.destroy() 



app=Application()

mainloop()

Answer 1

Store your button -variables within a class or just pass them to your functions. You got problems because of your button2 is out of scope!

Try this instead:

   def correct(self):
        username = self.entry.get()
        if username == self.username:
            self.button1 = Button(self.root, text='LOGIN', highlightbackground="green",
                                  width=28, command=self.root.destroy)
            self.button1.pack()
        elif username != self.username:
            self.button2 = Button(self.root,
                                  text="INCORRECT- CLICK TO DIMISS THIS MESSAGE",
                                  highlightbackground="red", width=48,
                                  command=self.incorrect)
            self.button2.pack()

    def incorrect(self):
        self.button2.destroy()