在 OptionMenu Tkinter 中选择选项时如何将按钮状态从禁用更改为活动

Question

当在选项菜单中选择一个选项时，我试图更改按钮状态，但没有任何变化。谁能告诉我我做错了什么？from tkinter import *def setLabel():    changed.set("Active")    def changeState():    pick = choose.get()    if (pick == "op2"):        button['state'] = button.ACTIVE        button.config(text = "ACTIVE")    else:        button['state'] = app.DISABLED        button.config(text = "Disabled")app = Tk()app.resizable(40,40)choose = StringVar()choose.set("op1")options = OptionMenu(app, choose, "op1", "op2")options.pack()button = Button(app, text = "Disabled", state = DISABLED, command = setLabel)button.pack()changed = StringVar()label = Label(app, textvariable = changed, font = ("helvetica", 10))label.pack()app.mainloop()

Answer 1

将您的功能更改为：

def changeState():

    pick = choose.get()

    if (pick == "op2"):

        button['state'] = ACTIVE #means active state

        button.config(text = "ACTIVE")

    else:

        button['state'] = DISABLED #means disabled state

        button.config(text = "Disabled")

另外，您没有调用您的函数，因此要调用它并使效果处于活动状态，请在选项菜单中添加命令参数，例如：

options = OptionMenu(app, choose, "op1", "op2",command=lambda _:changeState())

使用lambda _:optionmenu 命令需要传递一个 tkinter 变量，以避免这种情况。您还可以为您的函数提供一个参数，但是如果您在其他地方调用您的函数，您将必须传递一个参数，或者您也可以使用类似的参数并point=None摆脱lambda.

希望这可以清除错误，如果有任何疑问，请告诉我。

Answer 2

您可以在更改时command=changeState添加OptionMenu(...)调用：changeState()options

def changeState(pick):

    if pick == "op2":

        button['state'] = ACTIVE

        button.config(text = "ACTIVE")

    else:

        button['state'] = DISABLED

        button.config(text = "Disabled")

...

options = OptionMenu(app, choose, "op1", "op2", command=changeState)

Answer 3

知道了！

编辑：我稍微改变了第9行，删除了button.active并替换为NORMAL，这有效。

from tkinter import *

def setLabel():

    changed.set("Active")

    

def changeState(*args):

    pick = choose.get()

    if (pick == "op2"):

        button['state'] = NORMAL

        button.config(text = "ACTIVE")

    else:

        button['state'] = DISABLED

        button.config(text = "Disabled")

app = Tk()

app.resizable(40,40)

choose = StringVar()

choose.set("op1")

options = OptionMenu(app, choose, "op1", "op2")

choose.trace("w", changeState)

options.pack()

button = Button(app, text = "Disabled", state = DISABLED, command = setLabel)

button.pack()

changed = StringVar()

label = Label(app, textvariable = changed, font = ("helvetica", 10))

label.pack()

app.mainloop()