Tkinter not replacing Tk.Label after calling destroy() method

Question

I extended Tk.Label class in order to customize my needs, and for some odd reason is not destroying the object, even after calling the widget.destroy() , when I am updating values. So basically, I would end up with the self.update old value on bottom and new value on top of old value.

import tkinter as tk

class GUI(tk.Frame):
  def __init__(self, master, *args, **kwargs)
    tk.Frame.__init__(self, *args, **kwargs)
    self.master = master

    self.update = Label(self.master, "Select a value", 0, 0)

    btn = tk.Button(text="Select", command=self.update_btn)
    btn.grid(row=0, column=1)

  def update_btn(self):
    # Destroy method being called here
    self.update.destroy()
    self.update = Label(self.master, "New value", 0, 0)

class Label(tk.Label):
  def __init__(self, root, label_name, row, col, *args, **kwargs):
    tk.Label.__init__(self, *args, **kwargs)
    label = tk.Label(root, text=label_name, *args, **kwargs)
    label.grid(row=row, column=col)

Any help would be much appreciated.

Answer 1

Your class is weird. You create Label inside Label and you shows only inner label. And later you destroy outer label but it will not destroy inner label.

Correct version is

class Label(tk.Label):

    def __init__(self, root, label_name, row, col, *args, **kwargs):
       tk.Label.__init__(self, *args, master=root, text=label_name, **kwargs)
       self.grid(row=row, column=col)

In Python 3.x you can write it

class Label(tk.Label):

    def __init__(self, root, label_name, row, col, *args, **kwargs):
        super().__init__(*args, master=root, text=label_name, **kwargs)
        self.grid(row=row, column=col)

Now to update text you can use

self.update["text"] = "..."

or

self.update.config(text="...")

instead of `self.update.label["text"] = ...

---

EDIT: class GUI is also weird. You creat Frame but you don't show it (you don't use pack/grid) and you use main window as parent for Label . For Button you don't even set parent so you may get weird result in some situations.

import tkinter as tk


class GUI(tk.Frame):

  def __init__(self, master, *args, **kwargs):
      super().__init__(*args, master=master, **kwargs)

      # show frame
      self.pack()

      # add to frame (self)
      self.update = Label(self, "Select a value", 0, 0)

      # add to frame (self)
      btn = tk.Button(self, text="Select", command=self.update_btn)
      btn.grid(row=0, column=1)

  def update_btn(self):
      self.update['text'] = "New value"
      #self.update.config(text="New value")


class Label(tk.Label):

    def __init__(self, root, label_name, row, col, *args, **kwargs):
       super().__init__(*args, master=root, text=label_name, **kwargs)
       self.grid(row=row, column=col)


root = tk.Tk()
GUI(root)
root.mainloop()