每按一下按钮，Tkinter标签文本就会更改

Question

I have a basic Tkinter app with which I would like each Button press to update a Label with different values. I have created the Button & Label and am using a StringVar() to set the value of the Label.

button3 = tk.Button(self, text="Test", command=self.update_label)
button3.pack()

lab = tk.Label(self, textvariable=self.v)
lab.pack()

self.v = StringVar()
self.v.set('hello')

And then I have the following, currently not working function. My understanding is to implement some form of counter to track the Button presses, however I can not see a way of doing this after looking at other similar examples.

def update_label(self):
    click_counter = 0   # I have only included as I believe this is the way to go?
    texts = ['the first', 'the second', 'the third']
    for t in texts:
        self.v.set(t)

Would anyone know of a solution to this? Thanks in advance.

Answer 1

If the idea is to cycle through the list and change the label text every time the button is pressed, you could do something like this:

import sys
if sys.version_info < (3, 0):
    from Tkinter import *
else:
    from tkinter import *

class btn_demo:
    def __init__(self):
        self.click_count = 0
        self.window = Tk()
        self.btn_txt = 'Change label!'
        self.btn = Button(self.window, text=self.btn_txt, command=self.update_label)
        self.btn.pack()
        self.lab = Label(self.window, text="")
        self.lab.pack()
        mainloop()

    def update_label(self):
        texts = ['the first', 'the second', 'the third']
        self.click_count = (self.click_count + 1) % len(texts) 
        self.lab["text"] = texts[self.click_count]


demo = btn_demo()