1

嘿，过去一天我一直被这个简单的错误所困扰，并且无法通过它。这是我收到此错误消息的代码的一部分：

Exception in Tkinter callback
Traceback (most recent call last):
  File "/usr/lib/python3.2/tkinter/__init__.py", line 1402, in __call__
    return self.func(*args)
  File "/home/ppppwn3d/workspace/Python/JailBreakBob/JailBreakBob.py", line 110, in buttonclick_mainscreen
    gamescreen()
  File "/home/ppppwn3d/workspace/Python/JailBreakBob/JailBreakBob.py", line 58, in gamescreen
    if pressed == 8 and e1 == answerlistx[randomimage] and e2 == answerlisty[randomimage]:
NameError: global name 'pressed' is not defined

里面

def gamescreen():
    imagelist = ["1.gif","2.gif","3.gif","4.gif","5.gif","6.gif","7.gif","8.gif","9.gif","10.gif","11.gif","12.gif","13.gif","14.gif","15.gif","16.gif","17.gif","18.gif","19.gif","20.gif","21.gif","22.gif","23.gif","24.gif","25.gif","26.gif","27.gif","28.gif","29.gif","30.gif","31.gif","32.gif","33.gif","34.gif","35.gif","36.gif","37.gif","38.gif","39.gif","40.gif","41.gif","42.gif","43.gif","44.gif","45.gif","46.gif","47.gif","48.gif","49.gif","50.gif"]
    answerlistx = [-1, -3, 3, 4, -7, 8, 9, 10, -10, 2, -7, 7, -1, -5, -6, -9, -7, 10, -4, 8, 1, -8, -10, -1, -3, -7, -3, 7, 3, -4, 1, -8, -4, 9, -5, -10, 10, 2, 2, -10, 4, 9, -3, 6, 10, -6, 4, 9, -10, -10]
    answerlisty = [3, -6, -5, 3, -2, 4, -4, -3, 4, -6, 1, 2, 2, 3, 2, -1, -5, 1, -3, 1, -2, -2, -5, -3, -2, -6, -3, 6, 2, 0, -5, 6, -4, 4, 1, -6, 0, -6, 5, 2, 4, -4, -2, 0, -3, -6, -4, 1, -3, 1]

    canvas.bind("<Button-1>", buttonclick_gamescreen)
    canvas.pack(expand = YES, fill = BOTH)
    photo = PhotoImage(file="gamescreen.gif")
    canvas.create_image(1, 1, image = photo, anchor = NW)
    e1 = Entry(canvas, width = 11)
    e2 = Entry(canvas, width = 11)
    canvas.create_window(390, 501, window=e1, anchor = NW)
    canvas.create_window(551, 501, window=e2, anchor = NW)
    canvas.after(1, countdowntimer)
    while cdtimer != 0:
        randomimage = random.randrange(0,49+1)
        game = PhotoImage(file=imagelist[randomimage])
        images = canvas.create_image(30, 65, image = game, anchor = NW)
        if pressed == 8 and e1 == answerlistx[randomimage] and e2 == answerlisty[randomimage]:
             canvas.delete(images)
             randomimage = random.randrange(0,49+1)
             scorecounter = scorecounter + 1
             game = PhotoImage(file=imagelist[randomimage])
             images = canvas.create_image(30, 65, image = game, anchor = NW)
        elif pressed == 8 and e1 != answerlistx[randomimage] or e2 !=     answerlisty[randomimage]:
            wronganswer = canvas.create_text(400, 200, text="Incorrect", font="Ubuntu 29 bold", fill=red, anchor=NW)
            e1.delete(0.0,END)   
            e2.delete(0.0,END)
            canvas.after(1500,(canvas.delete(wronganswer)))

但我确实在

def buttonclick_gamescreen(event):
    global pressed
    pressed = ""

    if event.x >853 and event.x <957 and event.y > 8 and event.y < 56 : pressed = 7 
    if event.x >666 and event.x <947 and event.y > 491 and event.y < 534 : pressed = 8 
    if pressed == 7 :
        window.destroy()
    if pressed == 8:
        print("next button")

这让我很困惑。有人可以向我解释为什么会发生这种情况以及我应该做些什么来解决它？提前致谢

PS：基本上我在这里要做的是，当按下“下一步”按钮时，它将检查 e1 和 e2，如果那里的字符串与列表中的答案匹配，那么它将随机将另一个图像加载到画布上。

4

3 回答 3

1

尽管您已经在def buttonclick_gamescreen(event):中声明了全局变量 press ，但问题是您的def gamescreen():在def buttonclick_gamescreen(event):之前被调用，因此 python 运行时无法在内存中查找名为 press 的引用，因为那行代码从未执行过。为了演示这会如何产生影响，请考虑以下内容：

def do_something():
    global name
    name = 10
    print name

def do_somehting_else():
    if name == 10:
        print "Valid"

这里的名称是在函数体内全局定义的。所以，当我们调用：

do_something()
do_somehting_else()

我们得到，

>>> 10
>>> Valid

但是，如果我们将函数调用的顺序更改为：

do_somehting_else()
do_something()

python运行时抱怨：

Traceback (most recent call last):
  File "/home/rahul/workspace/PyTest/func.py", line 94, in <module>
    do_somehting_else()
  File "/home/rahul/workspace/PyTest/func.py", line 91, in do_somehting_else
    if name == 10:
NameError: global name 'name' is not defined

为了解决这个问题，如果您可以控制函数调用，请按正确的顺序执行它们。如果没有，请创建一个模块级别名称按下并直接在def gamescreen():中访问它，就像在def buttonclick_gamescreen(event):中所做的那样。基本上，像这样：

global pressed

希望这可以帮助 ：）。

于 2013-07-15T05:39:52.097 回答
1

您没有pressed在模块级别定义。至少你应该这样做：

pressed = ''

def buttonclick_gamescreen(event):
    global pressed
    ...
def gamescreen():
    ...

或者您可以将代码重新组织为一个类：

class Application(tk.Frame):
    def __init__(self, ...):
        self.pressed = ''
    def gamescreen():
        ...
    ...

或者您可以使用 aStringVar来跟踪该值。

于 2013-07-15T05:31:21.210 回答
0

问题是在您检查的地方之前没有执行定义pressed：

def gamescreen():
    # ...
    canvas.bind("<Button-1>", buttonclick_gamescreen)  # You only attach callback
    # ...  "pressed" still not defined
    while cdtimer != 0:
        # ...
        if pressed == 8:  # you access "pressed" here
            # ...

要么pressed在模块级别显式定义，要么显式调用buttonclick_gamescreen。

于 2013-07-15T05:32:40.940 回答