为什么 destroy() 在此代码中不起作用?

Why does destroy() not work in this code?

这是我正在尝试编写的一个简单测试脚本,它将帮助我自学 tkinter...

from tkinter import *
def hello():
   print("U pressed it lol")

global window1, window2
window2 = None
window1 = None

def setWindow(windowEnter):
   global window
   window = windowEnter
   window = Tk()
   window.attributes("-fullscreen", True)

def newScreen(newScreen, screenToDelete):
   setWindow(newScreen)
   print("New Window Created")
   screenToDelete.destroy()
   print("He ded lol")

setWindow(window1)

def setStuff():
   button = Button(window1, text="hey", command=hello)
   label = Label(window1, text="YoYoYo My dude")
   button2 = Button(window1, text="Next Page", command = lambda: newScreen(window2, window1))

   button.pack()
   label.pack()
   button2.pack()

setStuff()

当我运行这段代码时它returns出错了?

File "C:\Users6341\Desktop\test.py", line 19, in newScreen
screenToDelete.destroy()
AttributeError: 'NoneType' object has no attribute 'destroy'

为什么这不起作用?我该如何解决?

提前致谢:) (顺便说一句,我正在使用 python 3.6)

我现在无法对其进行测试,但我发现了一个错误来源:

lambda: newScreen(window2, window1)

这会创建一个不接受任何参数的 lambda 函数,因此 window2 和 window1 将为 None,并且 None 没有 destroy() 方法,因此会出现错误。而是尝试:

lambda window2, window1: newScreen(window2, window1)

你设置

window2 = None
window1 = None

作为全局变量然后定义button2的命令函数为

lambda: newScreen(window2, window1)

调用 newScreen 时 window2 和 window1 的值都是 None,因此出现错误。这里的根本问题是您的 setWindow 函数:

def setWindow(windowEnter):
    global window
    window = windowEnter
    window = Tk()
    window.attributes("-fullscreen", True)

这与您的使用方式不符。当您调用 setWindow(window1) 时,您传递了 window1,在全局范围内看不到该函数对变量所做的操作。一个简单的例子是:

def increment(a):
    a +=1
x = 1
print(x)
increment(x)
print(x)

这将打印 1 两次。

为了达到你想要的效果,我建议你使用字典来记录你的 windows。

from tkinter import *
def hello():
   print("U pressed it lol")

global window1, window2
windows = {}


def setWindow(window_name):
   windows[window_name] = Tk()
   windows[window_name].attributes("-fullscreen", True)

def newScreen(newScreen_name, screenToDelete_name):
   setWindow(newScreen_name)
   print("New Window Created")
   windows[screenToDelete_name].destroy()
   del windows[screenToDelete_name] #delete invalid entry from dict
   print("He ded lol")

setWindow("window1")

def setStuff():
   button = Button(windows["window1"], text="hey", command=hello)
   label = Label(windows["window1"], text="YoYoYo My dude")
   button2 = Button(windows["window1"], text="Next Page", command = lambda: newScreen("window2", "window1"))

   button.pack()
   label.pack()
   button2.pack()

setStuff()

旁注: 以前你的函数是 def newScreen(newScreen, screenToDelete),这非常 confusing/bad 风格,因为函数和它的第一个参数共享相同的姓名。无论如何我都改变了它以强调它现在将字符串作为参数,但请记住它以备将来使用。