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

我试图在选项菜单中选择一个选项时更改按钮状态，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

将您的函数更改为：

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")

另外你没有调用你的函数，所以要调用它并激活效果，在你的选项菜单上添加一个命令参数，比如：

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

使用 lambda _: 因为 optionmenu 命令期望传递一个 tkinter 变量，以避免这种情况。你也可以为你的函数设置一个参数，但如果你在其他地方调用你的函数，你将不得不传入一个参数，或者你也可以使用像 point=None 这样的参数并去掉 lambda。

希望这清除了错误，如果有任何疑问，请告诉我。

干杯

Answer 2

知道了！

编辑：我稍微更改了第 9 行，删除了 button.active 并替换为 NORMAL，这很有效。

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()

Answer 3

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

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)

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

How to change a buttons state from disabled to active when an option is selected in an OptionMenu Tkinter

python

python-3.x

tkinter

tkinter.optionmenu