Question

import tkinter as tk
panel = tk.Tk()
num = 42
lbl1 = tk.Label(panel, text = str(num))

我们说我有一个这样的功能和按钮：

def increase():
    lbl1.configure(text = str(num+1))

btn = tk.Button(panel, text = 'Increase', command = increase)

panel.mainloop()

按下按钮时，此按钮将使标签的编号增加1。但是，这只能在按钮完全没有任何功能之前工作一次。我怎样才能使每次按下按钮时，数字增加1？

Answer 1

您从未保存增加的num。

值

def increase():
    global num # declare it a global so we can modify it
    num += 1 # modify it
    lbl1.configure(text = str(num)) # use it

Answer 2

这是因为num总是43

import tkinter as tk
num = 42

def increase():
    global num
    num += 1
    lbl1.configure(text = str(num))


panel = tk.Tk()

lbl1 = tk.Label(panel, text = str(num))
lbl1.pack()
btn = tk.Button(panel, text = 'Increase', command = increase)
btn.pack()
panel.mainloop()

在Python 3中使用tkinter时，每次按下按钮时如何获得一个按钮来运行？

2 个答案: