在 class 之外更改 tkinter canvas 的文本

Question

    from tkinter import *

class MainBattle(Frame):
    def __init__(self, parent):
        Frame.__init__(self, parent)   
        self.parent = parent        
        self.initUI()
    def initUI(self):
        global canvas
        self.parent.title('Python')
        self.pack(fill = BOTH, expand = 1)
        canvas = Canvas(self)
        self.Label_My = Label(self, text = 'MyObject')


        self.Label_My.place(x = 470, y = 35)
        canvas.pack(fill = BOTH, expand = 1)
        canvas.update()
    def aa(self):
        self.Label_My['text'] = 'HisObject'

def Change():
    Label_My['text'] = 'HisObject'

root = Tk()
ex = MainBattle(root)
root.geometry('700x500')

应该用全局方法？如果可能，我会在 class 内定义标签，并在 class 外更改它的文本。

Answer 1

如果您的问题是 "can I use global to set variable values from outside the class" 那么是的。每当您想更改全局变量的值时，都需要编写 global.

def changetext():
   global label_text
   label_text = "new text"

Answer 2

您不需要全局变量。您有实例的引用，它允许您访问所有实例变量：

ex.Label_My["text"] = "HisObject"

在 class 之外更改 tkinter canvas 的文本

Change tkinter canvas's text outside the class

python

class

tkinter

label

self