Tkinter GUI重叠或刷新列表中的标签

Question

I'm trying to have a gui where the user can choose items from a scrollable list, but I'm having trouble printing out the chosen items once the checkbuttons have been selected. When I run the following code, the label I have at the end that prints out what the user selected doesn't refresh. So if the user changes their mind, picks different fruits, and then hits the button again, the gui doesn't reflect that.

My list, check_list , changes appropriately, but I basically need a way to clear out the GUI and label again. I feel like an easy way to do this would be to forget the frame (ie frame.pack_forget() ), but I haven't had any luck with it so far.

import tkinter as tk
from tkinter import *

mylist = ['apple','pear','kiwi','banana','strawberry','pineapple']

root = Tk()
root.geometry('400x100')

frame = Frame(root)
frame.pack(fill=BOTH, expand = True)

fruit_vars = []
check_list= []

def cb_checked():
    global check_list
    for ctr, int_var in enumerate(fruit_vars):
           if int_var.get():     ## IntVar not zero==checked
                temp = mylist[ctr]
                check_list.append(temp)

    #Keep only the unique fruits in list
    check_list_set = set(check_list)
    check_list = list(check_list_set)
    return check_list


#Create scrollable checkboxes of fruit options
text = tk.Text(root, cursor="arrow", width = 5, height = 5)
vsb = tk.Scrollbar(root, command=text.yview)
text.configure(yscrollcommand=vsb.set)
vsb.pack(side="right", fill="y")
text.pack(side="left", fill="both", expand=True)

for fruit in mylist:
    fruit_vars.append(tk.IntVar())
    cb = tk.Checkbutton(text, text=fruit, variable=fruit_vars[-1],
                        onvalue=1, offvalue=0, command=cb_checked)
    text.window_create("end", window=cb)
    text.insert("end", "\n")


#Print which fruits the user chose to the gui
def label_fruits():
    print(check_list)
    for fruits in check_list:
        Label(root, text=fruits).pack()

Button(root, text='Show Chosen Fruits', command=label_fruits).pack()

root.mainloop()

Answer 1

To do what you want, I added another list , named check_buttons , to retain the tkinter ids of each tk.Checkbutton created. This allows each one can be cleared later.

I also added another Frame container object to hold all the fruit name Label s. It's created on-the-fly in label_fruits() after first making an attempt to get rid of any existing one by calling list_frame.destroy() . It's then (re)created and a new set of Label s are put in it.

import tkinter as tk

mylist = ['apple', 'pear', 'kiwi', 'banana', 'strawberry', 'pineapple']

root = tk.Tk()
root.geometry('400x100')

frame = tk.Frame(root)
frame.pack(fill=tk.BOTH, expand=True)

checked_list = []
check_buttons = []  # Added.
fruit_vars = []

def cb_pressed():
    """ Checkbutton callback. """

    # (Re)create [the entire] list of checked fruits.
    checked_list.clear()
    for i, int_var in enumerate(fruit_vars):
       if int_var.get():  # Not zero -> checked.
            checked_list.append(mylist[i])


# Create scrollable Checkbuttons of fruit options.
text = tk.Text(root, cursor="arrow", width=5, height=5)
vsb = tk.Scrollbar(root, command=text.yview)
text.configure(yscrollcommand=vsb.set)
vsb.pack(side=tk.RIGHT, fill=tk.Y)
text.pack(side=tk.LEFT, fill=tk.BOTH, expand=tk.YES)

# Create IntVars and check_buttons list.
for fruit in mylist:
    fruit_vars.append(tk.IntVar())
    cb = tk.Checkbutton(text, text=fruit, variable=fruit_vars[-1],
                        onvalue=1, offvalue=0, command=cb_pressed)
    check_buttons.append(cb)
    text.window_create(tk.END, window=cb)
    text.insert(tk.END, "\n")


def label_fruits():
    """ Display the fruits user has checked. """

    global list_frame

    print(checked_list)

    try:
        list_frame.destroy()
    except NameError:  # Nonexistent.
        pass
    list_frame = tk.Frame(root)  # (Re)create Label container.
    list_frame.pack()
    for fruit in checked_list:
        tk.Label(list_frame, text=fruit).pack()

    # Clear out GUI by unchecking all the Checkbuttons.
    for cb in check_buttons:
        cb.deselect()


tk.Button(root, text='Show Chosen Fruits', command=label_fruits).pack()

root.mainloop()