Python ttk標籤錯誤，標籤undefined

Question

我已經爲鬧鐘寫了下面的代碼，發現它在GitHub上。但在我的代碼中，它拋出了一個錯誤，指出標籤沒有被定義。

import time as time, os as os 
from tkinter import * 
from tkinter import messagebox 
from tkinter import ttk # For buttons, labels, frames etc... 

root = Tk() # Creates the tkinter object root 
root.title('Alarm Clock') # Sets the window title 
root.geometry('200x200') # Sets the window dimension 


def submit_button(): # The core condition for the alarm clock 
    alarm_time = time_entry.get() 
    dialog_box() 
    #bottom_label.config(text ="The Alarm will Ring at {} ".format(AlarmTime)) #delayed in execution 
    current_time = time.strftime('%H:%M') # Sets the current_time format to Hours:Minutes 
    print('The alarm time is: {}' .format(alarm_time)) 
    while alarm_time != current_time: 
     current_time = time.strftime('%H:%M') # Sets the current_time format to Hours:Minutes 
     time.sleep(1) # To give a delay in while loop 
    if alarm_time == current_time: # When current_time is alarm time 
     os.system('start alarm-music.mp3') # Play the music from the os 
     bottom_label.config(text="Alarm music playing....") 
     messagebox.showinfo(title='Alarm Message', message="{}".format(entry2.get())) 


def dialog_box(): 
    alarm_time = time_entry.get() 
    messagebox.showinfo("Alarm Clock", "alarm will ring at {}" .format(alarm_time)) # title and display of dialog box. 
    bottom_label.config(text = "The alarm time is counting...") # configures the text below submit button 


# Frame creation 
alarm_frame = ttk.Frame(root) # Creates a frame named alarm_frame 
alarm_frame.config(height=200, width=200) # Sets the dimensions of the frame 
alarm_frame.pack() 

# Alarm Label 
alarm_label = ttk.Label(alarm_frame, text = "Enter the alarm time:") # Creates a label with text Enter alarm time 
alarm_label.pack() # Unpacks the label onto the frame 

# Entering time 
time_entry = ttk.Entry(alarm_frame, width=30) 
time_entry.insert(3, 'example: 13:15') 
time_entry.pack() # Unpacks the entry on the frame 

# Message label 
message_label = ttk.Label(alarm_frame, text = "Enter message to display:") 
message_label.pack() 

# Entering Message 
message_entry = ttk.Entry(alarm_frame, width = 30) # Facilitates entering alarm message 
message_entry.pack() # Unpacks the entry area 

# Creation of submit button 
submit = ttk.Button(alarm_frame, text = 'submit', command = submit_button())  
submit.pack() # Unpacks the button onto the frame 


# Bottom label creation 
bottom_label = ttk.Label(alarm_frame) # Label(master, **kw) 
bottom_label.pack() # unpacks the bottom_label on the frame 

root.mainloop() 

它說bottom_label沒有在dialog_box（）中定義爲什麼會發生這種情況？

Answer 1

用途：

... 
# Bottom label creation 
bottom_label = ttk.Label(alarm_frame) # Label(master, **kw) 
bottom_label.pack() # unpacks the bottom_label on the frame 

# Creation of submit button 
submit = ttk.Button(alarm_frame, text = 'submit', command = submit_button())  
submit.pack() # Unpacks the button onto the frame 
... 

相反的：

... 
# Creation of submit button 
submit = ttk.Button(alarm_frame, text = 'submit', command = submit_button())  
submit.pack() # Unpacks the button onto the frame 


# Bottom label creation 
bottom_label = ttk.Label(alarm_frame) # Label(master, **kw) 
bottom_label.pack() # unpacks the bottom_label on the frame 
... 

秩序的問題，你有command=使用它之前初始化bottom_label。