Question

我不知道为什么会出现NameError错误。

代码：

from tkinter import*
from tkinter import font
import random
from tkinter import filedialog as fd
from tkinter import messagebox
def converter():
    from tkinter import font
    import os
    num = random.choice('123456789')
    alpha = random.choice('abcdefghijklmnopqrstuvwxyz')

    name = num + alpha

    gui_con = Tk()
    gui_con.geometry("500x530")
    font = font.Font(family='Helvetica', size=25, weight='bold')
    address = ''
    gui_con.resizable(0, 0)
    gui_con.title('                                                   CONVERTER')
    gui_con.configure(bg='snow')

    def choose_file():
        global address
        global image
        address = fd.askopenfilename(parent=gui_con)
        label['text'] = address
        image = open(address)

    def convert_file():
        global image
        global label
        global address
        top = Toplevel()

        def convert_png():
            global image
            global address
            global label
            if label['text'] == '':
                messagebox.showerror('ERROR', 'Select any file from above', parent=gui_con)
                top.destroy()
            else:
                image.save(r'Converter_Img' + '\\' + name + '.png')
                label['text'] = ''
                address = ''

        def convert_jpg():
            global image
            global label
            global address
            if label['text'] == '':
                messagebox.showerror('ERROR', 'Select any file from above', parent=gui_con)
                top.destroy()
            else:
                image.save('Converter_Img' + '\\' + name + '.jpg')
                label['text'] = ''
                address = ''

        def convert_ico():
            global image
            global label
            global address
            if label['text'] == '':
                messagebox.showerror('ERROR', 'Select any file from above', parent=gui_con)
                top.destroy()
            else:
                image.save(r'Converter_Img' + '\\' + name + '.ico')
                label['text'] = ''
                address = ''

        def convert_jpeg():
            global image
            global label
            global address
            if label['text'] == '':
                messagebox.showerror('ERROR', 'Select any file from above', parent=gui_con)
                top.destroy()
            else:
                image.save(r'Converter_Img' + '\\' + name + '.jpeg')
                label['text'] = ''
                address = ''

        top.title('CONVERT')
        top.geometry('300x350')
        top.configure(bg='snow')
        Button(top, text='Convert To PNG', font=('Helvetica', 15, 'bold'), bd=6, command=convert_png,
               bg='dodger blue2').pack(pady=20)

        Button(top, text='Convert To JPG', font=('Helvetica', 15, 'bold'), bd=6, command=convert_jpg,
               bg='dodger blue2').pack(pady=10)

        Button(top, text='Convert To ICO', font=('Helvetica', 15, 'bold'), bd=6, command=convert_ico,
               bg='dodger blue2').pack(pady=20)

        Button(top, text='Convert To JPEG', font=('Helvetica', 15, 'bold'), bd=6, command=convert_jpeg,
               bg='dodger blue2').pack(pady=10)
        top.resizable(0, 0)

        top.mainloop()

    def folder():
        os.startfile('Converter_Img')

    Label(gui_con, text='Converter', font=font, foreground='blue', bg='snow').pack(pady=40)

    Button(gui_con, text='Choose File', font=font, bd=6, command=choose_file, bg='dodger blue2').pack()

    label = Label(gui_con, text='', font=('Helvetica', 10, 'bold'), bg='snow', foreground='black')
    label.pack(pady=20)

    Button(gui_con, text='CONVERT', font=font, bd=6, command=convert_file, bg='dodger blue2').pack()

    Button(gui_con, text='Output_Folder', font=font, bd=6, command=folder, bg='dodger blue2').pack(pady=50)

    gui_con.mainloop()


converter()

错误：

Exception in Tkinter callback
Traceback (most recent call last):
  File"~~\Python\Python37-32\lib\tkinter\__init__.py", line 1705, in __call__
    return self.func(*args)
  File "~~/scratch_1.py", line 63, in convert_ico
    if label['text'] == '':
NameError: name 'label' is not defined

预先感谢

Answer 1

由于将label变量定义为全局变量，但在全局命名空间中没有名为label的变量，因此收到错误消息。相反，您在label函数的范围内拥有converter()。

Answer 2

您需要考虑的是，定义全局变量还不够，还需要声明一个值。

我找不到您定义的标签行，请在脚本顶部执行label={}并查看其是否有效

NameError：未定义名称“标签”

2 个答案: