如何删除框架的内容

Question

I have a Frame which is filled up with several Label . The text in all the Label is recalculated on a regular basis and I would like to erase everything in the Frame before.

Initially I thought that it would be enough to replace the text of the Label :

import Tkinter as tk

class MyApp():
    def __init__(self):
        self.counter = 0
        self.root = tk.Tk()
        self.frame = tk.Frame(self.root)
        self.frame.grid(row=0, column=0)  # typo edited following the answer
        self.root.bind('q', self.toggle)


    def toggle(self, event):
        self.counter += 1
        if self.counter % 2 == 0:
            text = "hello {}".format(self.counter)
            bg = "green"
        else:
            text = "very long text, longer than hello {}".format(self.counter)
            bg = "blue"
        # the tk.Label call is not assigned to a variable on purpose
        tk.Label(self.frame, text=text, bg=bg).grid(row=0, column=0)

app = MyApp()
app.root.mainloop()

The text is not replaced, though, but the longer one stays:

How can I erase the contents of the Frame without erasing each of its elements?

Please note that the tk.Label call is not assigned a variable to, I have several Label and do did not need to keep track of them, once they are displayed. I could, I guess, keep a list of all the Label and .grid_forget() them but if there is a simpler solution it would bring a cleaner code.

Answer 1

Since you are always using the same label, you can create it in your __init__ method and then configure it in you callback:

def __init__(self):
    # ...
    self.frame = tk.Frame(self.root).grid(row=0, column=0)
    self.label = tk.Label(self.frame)
    self.label.grid()
    self.root.bind('q', self.toggle)


def toggle(self, event):
    self.counter += 1
    # ...
    # the tk.Label call is not assigned to a variable on purpose
    self.label.config(text=text, bg=bg)

---

UPDATE: Since you don't want to use any variable for the label, you can destroy all the children of the frame:

def toggle(self, event):
    # ...
    for children in self.frame.winfo_children():
        children.destroy()
    tk.Label(self.frame, text=text, bg=bg).grid(row=0, column=0)

Keep in mind that the call to grid() returns None , so in your original example the variable self.frame does not contain the widget reference:

def __init__(self):
    self.counter = 0
    self.root = tk.Tk()
    self.frame = tk.Frame(self.root)
    # WRONG
    # self.frame = tk.Frame(self.root).grid(row=0, column=0)
    # RIGHT
    self.frame.grid() # row=0, column=0 comes by default