python tkinter-按下按钮时覆盖标签

Question

 def button_pressed(item_name, item_price):
    global lbl
    for v1, v2 in zip(item_name, item_price):
        item_values = '{} {}'.format(v1, v2)
        sv = StringVar()
        lbl = Label(shop_window, height="2", textvariable=sv, anchor = NW).grid(columnspan = 4)
        sv.set(item_values)

# Create initial shopping cart window

shop_window = Tk()
shop_window.title('Welcome to the Outlet')
shop_window.geometry("1200x900")
shop_window.resizable(0, 0)


introduction_text = Label(shop_window, text = 'Welcome to the Shopping Outlet', font = ('Arial', 30))

electronics_button = Button(shop_window, text = 'Buy Electronics', font = ('Arial', 18), command = lambda:button_pressed(electronics_name, electronics_price))
books_button = Button(shop_window, text = 'Buy Books', font = ('Arial', 18), command = lambda:button_pressed(books_name, books_price))
kitchen_button = Button(shop_window, text = 'Buy Kitchen', font = ('Arial', 18), command = lambda:button_pressed(kitchen_name, kitchen_price))
monitors_button = Button(shop_window, text = 'Buy Kitchen', font = ('Arial', 18), command = lambda:button_pressed(monitors_name, monitors_price))

introduction_text.grid(row = 0, column = 0, columnspan = 4, sticky = N )

electronics_button.grid(row = 2, column = 0)
books_button.grid(row = 2, column = 1)
kitchen_button.grid(row = 2, column =2)
monitors_button.grid(row = 2, column = 3)

我创建了这个tk窗口，以显示每个类别10个项目的购物清单。 每个类别都有两个列表，即item_name / item_price（已从亚马逊网站刮下）。

当我运行程序时，我可以按一下按钮，列表将正确显示，但是如果再次按一下，它将在以前制作的标签的末尾添加新标签。 我的问题是例如如何使程序覆盖以前的标签。 按“购买电子产品”可根据需要创建我的标签，但在添加更多标签后按“购买书籍”。 我想改写“购买电子产品”标签。 我认为这将是某种global lbl但不确定。

Answer 1

请参阅具有已创建功能的示例上的，为此，您需要使用lbl["text"] = sv覆盖当前位置，然后覆盖

def button_pressed(item_name, item_price):
    global lbl
    for v1, v2 in zip(item_name, item_price):
        item_values = '{} {}'.format(v1, v2)
       # sv = StringVar()
        lbl["text"] = sv
        sv.set(item_values)

然后在root和mainloop内创建Label

shop_window = Tk()

sv = StringVar()
lbl = Label(shop_window, height="2", textvariable=sv, anchor = NW)
lbl.grid(columnspan = 4)


shop_window = Tk()

Answer 2

您可以为标签创建框架

f = Frame(shop_window)
f.grid(row=3, column=0, columnspan=4)

然后在回调函数中销毁框架的所有子节点并创建新的子节点

def button_pressed(item_name, item_price):
    for widget in f.winfo_children():
        widget.destroy()
    for v1, v2 in zip(item_name, item_price):
        item_values = '{} {}'.format(v1, v2)
        Label(f, height="2", text=item_values).pack()