如何在 Tkinter Python 中更新子函数内的标签

Question

我正在尝试编写一个添加用户选择的数字并在每次单击按钮后显示总和的函数。此功能是更大程序的一部分。因此我必须把它放在一个类或一个函数中。

程序在函数外运行

import Tkinter as tk   


total = 0
def Sum():
    global total
num = var.get()
total = num+ total
label.config(text = total)

root = tk.Tk()
var = tk.IntVar()

numbers = [("1"),
           ("2"),
           ("3"),
           ("4"),
           ("5")]


for val, choice in enumerate(numbers):
    tk.Radiobutton(root,
                   text=choice,
                   indicatoron = 0,
                   width = 5,
                   padx = 100,
                   variable=var,
                   command=Sum,
                   value=val).pack()

label = tk.Label(root, width = 30, height = 3, bg = "yellow")
label.pack()

root.mainloop()

但是当我把它放在这样的函数中时

import Tkinter as tk  

def func():

   total = 0
   def Sum():
       global total
       num = var.get()
       total = num+ total
       label.config(text = total)

   root = tk.Tk()
   var = tk.IntVar()

   numbers = [("1"),
              ("2"),
              ("3"),
              ("4"),
              ("5")]


   for val, choice in enumerate(numbers):
       tk.Radiobutton(root,
                      text=choice,
                      indicatoron = 0,
                      width = 5,
                      padx = 100,
                      variable=var,
                      command=Sum,
                      value=val).pack()

   label = tk.Label(root, width = 30, height = 3, bg = "yellow")
   label.pack()

   root.mainloop()

func()

它抛出了以下错误：

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Python27\lib\lib-tk\Tkinter.py", line 1532, in __call__
    return self.func(*args)
  File "C:\Python27\Gui_demo.py", line 9, in Sum
    total = num+ total
NameError: global name 'total' is not defined

我是 Python 新手，希望有一个简单的解决方法。任何帮助，将不胜感激。谢谢

Answer 1

我的建议是将您的应用放在一个类中而不是嵌套函数中。

class App:

    total = 0

    def __init__(self):
        root = tk.Tk()
        self.var = tk.IntVar()

        numbers = [("1"),
              ("2"),
              ("3"),
              ("4"),
              ("5")]


        for val, choice in enumerate(numbers):
            tk.Radiobutton(root,
                      text=choice,
                      indicatoron = 0,
                      width = 5,
                      padx = 100,
                      variable=self.var,
                      command=self.Sum,
                      value=val+1).pack()

        self.label = tk.Label(root, width = 30, height = 3, bg = "yellow")
        self.label.pack()

        root.mainloop()

    def Sum(self):
        num = self.var.get()
        App.total += num
        self.label.config(text = App.total)

App()