Python tkinter 类型错误：'NoneType' 对象没有长度

Question

我写了一个程序，你可以在一个滑动条上选择你想要的单词数量。当我把滑动条调到1，然后试着把这个值打印到标签上时，我遇到了一个错误：

Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Python33\lib\tkinter\__init__.py", line 1475, in __call__
return self.func(*args)
File "C:\Users\Eduard\Desktop\Zeugs\python\test.py", line 69, in ok3
label['text']=random.choice(WORDS)
File "C:\Python33\lib\random.py", line 249, in choice
i = self._randbelow(len(seq))
TypeError: object of type 'NoneType' has no len()

这是我的代码：

import tkinter as tk
from tkinter import *
import random
from functools import partial

class SampleApp(tk.Tk):
    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)

        container= tk.Frame(self)
        container.pack(side="top", fill="both", expand=True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)

        self.frames={}
        for F in (mode2, scale1):
            frame= F(container, self)
            self.frames[F]=frame
            frame.grid(row=0, column=0, sticky="nsew")

        self.show_frame(mode2)

    def show_frame(self, c):
        frame=self.frames[c]
        frame.tkraise()

class mode2(tk.Frame):
    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)

        def antmenge(self):
            label1["text"]="Mögliche Antworten: " \
                + str(antmengen.get()) + " "

        label1=tk.Label(self, text="Mögliche Antworten: 0 Wörter", width=25)
        label1.pack()

        antmengen=IntVar()
        antmengen.set(0)

        antm=Scale(self, width=20, length=200, orient="vertical", from_=0, to=20,
        resolution=1, tickinterval=10, label="Wörter", command=antmenge(self),
        variable=antmengen)
        antm.pack()

        def abfrage():
            if antmengen.get()==1:
                button3=Button(self, text="push again", command=lambda: controller.show_frame(scale1))
                button3.pack()

        button2=tk.Button(self, text="push", command=abfrage)
        button2.pack()

class scale1(tk.Frame):
    def __init__(self, parent, controller):
        tk.Frame.__init__(self, parent)
        label1=Label(self, text="Wort1")
        label1.pack()
        wort1auf=Entry(self)
        wort1auf.pack()

        label=tk.Label(self, text=" ")
        label.pack()

        a=label.configure(text=(wort1auf.get()))

        def ok3(label):
            WORDS=(a)
            label['text']=random.choice(WORDS)

        button1=tk.Button(self, text="push", command=partial(ok3, label))
        button1.pack()

if __name__== "__main__":
    app=SampleApp()
    app.mainloop()

抱歉，如果我的英语不好。

Answer 1

好的

那么我们开始吧。

    a=label.configure(text=(wort1auf.get()))
    def ok3(label):
        WORDS=(a)
        label['text']=random.choice(WORDS)

你遇到错误的原因是，变量a和WORDS都是None，因为label.configure(...)返回的是None。

我猜WORD是你想要选择的单词列表。我不太确定你提到的“a”是什么意思，你是想用输入的单词来填充它吗？如果是这样，WORDS=(a)是可以的，但你需要把“a”放到“ok3”里面。

    def ok3(label):
        a=label.configure(text=(wort1auf.get()))
        WORDS=(a)
        label['text']=random.choice(WORDS)

其次，它应该获取输入的值。

    def ok3(label):
        WORDS=(wort1auf.get()) # this will choose a random letter out of your input. 
        #WORDS=(wort1auf.get(),) # this will choose a the input word, since it is the only word inside the tuple. 
        WORDS=(a)
        label['text']=random.choice(WORDS)

希望这能帮到你。

祝好，

丹尼尔