Python tkinter 复选框即使被选中也总是返回值为 0

Question

它应该是一个 GUI 披萨订单表格，所以它有更多但我遇到的问题是当它获取一个应该是 OliveSelection 的变量时，它总是在检查时返回 0 而不是 1。

from tkinter import *
myGui=Tk()
myGui.geometry("800x600")
myGui.title("Pete's Pizza Parlour~Order Form")


TOPPING SELECTION
    toppings_lbl=Label(myGui,text="Toppings:",font=("Good Times",10),fg="blue").pack()
    a=IntVar()
    olives_chk=Checkbutton(myGui,text="Olives",variable=a).pack()
    b=IntVar()
    tomatoes_chk=Checkbutton(myGui,text="Tomatoes",variable=b).pack()
    c=IntVar()
    pepperoni_chk=Checkbutton(myGui,text="Pepperoni",variable=c).pack()
    d=IntVar()
    hotPeppers_chk=Checkbutton(myGui,text="Hot Peppers",variable=d).pack()
    e=IntVar()
    onions_chk=Checkbutton(myGui,text="Onions",variable=e).pack()
    f=IntVar()
    ham_chk=Checkbutton(myGui,text="Ham",variable=f).pack()
    g=IntVar()
    sausage_chk=Checkbutton(myGui,text="Sausage",variable=g).pack()
    h=IntVar()
    greenPeppers_chk=Checkbutton(myGui,text="Green Peppers",variable=h).pack()

olivesSelection=a.get()
tomatoesSelection=b.get()
pepperoniSelection=c.get()
hotPeppersSelection=d.get()
onionsSelection=e.get()
hamSelection=f.get()
sausageSelection=g.get()
greenPeppersSelection=h.get()

olivesSelectionStr="olives"
tomatoesSelectionStr="tomatoes"
pepperoniSelectionStr="pepperoni"
hotPeppersSelectionStr="hot peppers"
onionsSelectionStr="onions"
hamSelectionStr="ham"
sausageSelectionStr="sausage"
greenPeppersSelectionStr="green peppers"
noToppingsStr="no toppings."
def checkToppings():
    toppingsList=""
    if(olivesSelection==1):
        toppingsList=toppingsList+olivesSelectionStr
    elif(tomatoesSelection==1):
        toppingsList=toppingsList+tomatoesSelectionStr
    elif(pepperoniSelection==1):
        toppingsList=toppingsList+pepperoniSelectionStr
    elif(hotPeppersSelection==1):
        toppingsList=toppingsList+hotPeppersSelectionStr
    elif(onionsSelection==1):
        toppingsList=toppingsList+onionsSelectionStr
    elif(hamSelection==1):
        toppingsList=toppingsList+hamSelectionStr
    elif(sausageSelection==1):
        toppingsList=toppingsList+sausageSelectionStr
    elif(greenPeppersSelection==1):
        toppingsList=toppingsList+greenPeppersSelectionStr
    else:
        toppingsList=noToppingsStr

橄榄选择总是返回 0 而不是 1 当它应该被选中时 print(olivesSelection)

Answer 1

1. 您的程序中没有myGui.mainloop()。
2. TOPPING SELECTION 不是有效的声明。此外，以下行不需要缩进。
3. 不要单行创建和放置tkinter 小部件，否则最终会得到一大堆引用None 的变量（pack() 返回的值）。李>
4. olivesSelection=a.get() 之类的声明并没有按照您的想法行事。该语句调用a.get()，获得返回值0（因为它发生在程序启动时），然后将0 分配给olivesSelection。复选框不会更改该变量的值。如果您希望在选中复选框时动态发生事情，您必须 trace() 那些 IntVars 并将 commands 添加到 Checkbuttons。
5. checkToppings() 永远不会被调用。
6. 检查olivesSelection==1 是否总是False，因为a.get() 在分配给olivesSelection 时是0（见上文）。在此处使用a.get()。
7. 如果您在checkToppings() 中使用elif，它只会在列表中添加一个顶部（第一个带有复选框的顶部）。
8. 您不需要将==1 用于仅是0 或1 的值 - 只需说if pepperoniSelection:。 1 是真值，0 是假值（从技术上讲，1 实际上是 True，0 实际上是 False，因为 bool 是 int 的子类）。

---

from tkinter import *
myGui=Tk()
myGui.geometry("800x600")
myGui.title("Pete's Pizza Parlour~Order Form")


def checkem():
    print(a.get(), b.get(), c.get(), d.get(), e.get(), f.get(), g.get(), h.get())
    print(checkToppings())

toppings_lbl=Label(myGui,text="Toppings:",font=("Good Times",10),fg="blue")
toppings_lbl.pack()
a=IntVar()
olives_chk=Checkbutton(myGui,text="Olives",variable=a)
olives_chk.pack()
b=IntVar()
tomatoes_chk=Checkbutton(myGui,text="Tomatoes",variable=b)
tomatoes_chk.pack()
c=IntVar()
pepperoni_chk=Checkbutton(myGui,text="Pepperoni",variable=c)
pepperoni_chk.pack()
d=IntVar()
hotPeppers_chk=Checkbutton(myGui,text="Hot Peppers",variable=d)
hotPeppers_chk.pack()
e=IntVar()
onions_chk=Checkbutton(myGui,text="Onions",variable=e)
onions_chk.pack()
f=IntVar()
ham_chk=Checkbutton(myGui,text="Ham",variable=f)
ham_chk.pack()
g=IntVar()
sausage_chk=Checkbutton(myGui,text="Sausage",variable=g)
sausage_chk.pack()
h=IntVar()
greenPeppers_chk=Checkbutton(myGui,text="Green Peppers",variable=h)
greenPeppers_chk.pack()
thebutton = Button(myGui, text='check', command=checkem)
thebutton.pack()

olivesSelectionStr="olives"
tomatoesSelectionStr="tomatoes"
pepperoniSelectionStr="pepperoni"
hotPeppersSelectionStr="hot peppers"
onionsSelectionStr="onions"
hamSelectionStr="ham"
sausageSelectionStr="sausage"
greenPeppersSelectionStr="green peppers"
noToppingsStr="no toppings."

def checkToppings():
    toppings = [var for val,var in zip((a.get(), b.get(), c.get(), d.get(),
                                        e.get(), f.get(), g.get(), h.get()),
                                       (olivesSelectionStr, tomatoesSelectionStr,
                                        pepperoniSelectionStr, hotPeppersSelectionStr,
                                        onionsSelectionStr, hamSelectionStr,
                                        sausageSelectionStr, greenPeppersSelectionStr))
                if val]
    if not toppings:
        return 'no toppings.'
    elif len(toppings)==1:
        return toppings[0] + '.'
    elif len(toppings)==2:
        return ' and '.join(toppings) + '.'
    else:
        return ', '.join(toppings[:-1]) + ', and ' + toppings[-1] + '.'

myGui.mainloop()

Answer 2

好的，有几件事。

您需要在需要浇头的定义中包含 topping.get()。否则你只是在运行程序时执行.get() 而不是按需执行

TOPPING SELECTION 应该被注释掉，因为它没有其他用途

elif 大树不会对您有帮助，因为一旦您做出if 语句之一True，您将退出if 块。此外，作为个人喜好和代码清洁度的问题，您可能需要为此查找字典。一旦你在一个块中超过 3 或 4 个 if 语句，它们就会变得相当混乱。

另外，我知道你说还有更多代码，但作为一个友好的提醒，以防你忘记了其余代码的底部，请务必让你的主窗口实例输入mainloop()

from tkinter import *
myGui=Tk()
myGui.geometry("800x600")
myGui.title("Pete's Pizza Parlour~Order Form")

#TOPPING SELECTION
toppings_lbl=Label(myGui,text="Toppings:",font=("Good Times",10),fg="blue").pack()
a=IntVar()
olives_chk=Checkbutton(myGui,text="Olives",variable=a).pack()
b=IntVar()
tomatoes_chk=Checkbutton(myGui,text="Tomatoes",variable=b).pack()
c=IntVar()
pepperoni_chk=Checkbutton(myGui,text="Pepperoni",variable=c).pack()
d=IntVar()
hotPeppers_chk=Checkbutton(myGui,text="Hot Peppers",variable=d).pack()
e=IntVar()
onions_chk=Checkbutton(myGui,text="Onions",variable=e).pack()
f=IntVar()
ham_chk=Checkbutton(myGui,text="Ham",variable=f).pack()
g=IntVar()
sausage_chk=Checkbutton(myGui,text="Sausage",variable=g).pack()
h=IntVar()
greenPeppers_chk=Checkbutton(myGui,text="Green Peppers",variable=h).pack()

olivesSelectionStr="olives"
tomatoesSelectionStr="tomatoes"
pepperoniSelectionStr="pepperoni"
hotPeppersSelectionStr="hot peppers"
onionsSelectionStr="onions"
hamSelectionStr="ham"
sausageSelectionStr="sausage"
greenPeppersSelectionStr="green peppers"
noToppingsStr="no toppings."


def checkToppings():
    toppingsList=""
    olivesSelection=a.get()
    tomatoesSelection=b.get()
    pepperoniSelection=c.get()
    hotPeppersSelection=d.get()
    onionsSelection=e.get()
    hamSelection=f.get()
    sausageSelection=g.get()
    greenPeppersSelection=h.get()
    if(olivesSelection==1):
        toppingsList=toppingsList+olivesSelectionStr
    if(tomatoesSelection==1):
        toppingsList=toppingsList+tomatoesSelectionStr
    if(pepperoniSelection==1):
        toppingsList=toppingsList+pepperoniSelectionStr
    if(hotPeppersSelection==1):
        toppingsList=toppingsList+hotPeppersSelectionStr
    if(onionsSelection==1):
        toppingsList=toppingsList+onionsSelectionStr
    if(hamSelection==1):
        toppingsList=toppingsList+hamSelectionStr
    if(sausageSelection==1):
        toppingsList=toppingsList+sausageSelectionStr
    if(greenPeppersSelection==1):
        toppingsList=toppingsList+greenPeppersSelectionStr
    if toppingsList=="":
        toppingsList=noToppingsStr
    print(toppingsList)

topping_btn = Button(myGui,text='print toppings', command = checkToppings)
topping_btn.pack()
myGui.mainloop()