我正在使用 tkinter 和 urllib 制作一个类似于下载管理器的程序。在接近完成程序时，我意识到我没有为下载定义取消按钮。在进一步研究后，我发现了 multiprocessing（之前我只使用了线程），它是一个比线程更好的模块，用于并行运行函数，并且还具有终止功能。然而，无论我怎么做，我似乎都无法理解这个模块。它比线程复杂得多，而且我经常遇到荒谬的错误。在我的程序中，我经常会遇到以下错误：
Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Users\Family\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__init__.py", line 1883, in __call__
return self.func(*args)
File "C:/Users/Family/PycharmProjects/8-bit Downloader/test.py", line 258, in start_download
Process(target=download_files,
File "C:\Users\Family\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\process.py", line 121, in start
self._popen = self._Popen(self)
File "C:\Users\Family\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\context.py", line 224, in _Popen
return _default_context.get_context().Process._Popen(process_obj)
File "C:\Users\Family\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\context.py", line 327, in _Popen
return Popen(process_obj)
File "C:\Users\Family\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\popen_spawn_win32.py", line 93, in __init__
reduction.dump(process_obj, to_child)
File "C:\Users\Family\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\reduction.py", line 60, in dump
ForkingPickler(file, protocol).dump(obj)
TypeError: cannot pickle '_tkinter.tkapp' object
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "C:\Users\Family\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\spawn.py", line 116, in spawn_main
exitcode = _main(fd, parent_sentinel)
File "C:\Users\Family\AppData\Local\Programs\Python\Python38-32\lib\multiprocessing\spawn.py", line 126, in _main
self = reduction.pickle.load(from_parent)
EOFError: Ran out of input
我完全不知道是什么导致了这个错误以及如何修复它。似乎 start_download() 函数存在问题。以下是我的代码（我知道代码有一些缺陷，我可以在完成基础部分后将其清理干净，如果您认为某些部分与主题无关，请告诉我。）：
import os
import sqlite3
import time
import urllib.request
from multiprocessing import Process
from pathlib import Path
from tkinter import *
from tkinter import filedialog
from tkinter import font
from tkinter import messagebox
from tkinter import ttk
import numpy as np
import requests
import win10toast
from PIL import Image, ImageTk
files_downloading, times_clicked, dir_files = 0, 0, {}
info_window, customize = None, None
# The problem I believe is with the two functions below and the start function some of the code is related to the downloads tab
# which is irrelevant and some other were just functions that were unrelated so if you see a button without a function that
# exists or it is 'None' it is just deleted for the purpose of this question and also ignore the image variables!
def get_info(path, new_fullname, url_entry):
global times_clicked
lbl_await.pack_forget()
prg_br.pack_forget()
file_size = int(requests.head(str(url_entry.get()),
headers={'accept-encoding': ''}).headers['Content-Length']) / 1000000
print(file_size)
file_dir = Path(str(path).replace(" \ ".strip(), "/") + "/" + new_fullname)
size_eachsec = np.array([0.0, ])
my_scrollbar.pack(side=RIGHT, fill=Y)
lbl_fr = ttk.LabelFrame(second_frame, text=new_fullname, padding=5)
if len(new_fullname) > 20:
lbl_fr.config(text=new_fullname[:21] + "...")
download_prg = ttk.Progressbar(lbl_fr, orient=HORIZONTAL, length=365, mode='determinate', cursor="wait")
lbl_speed = Label(lbl_fr, text=None)
lbl_crnt_size = Label(lbl_fr, text=None)
lbl_file_size = Label(lbl_fr, text=f"File size: {round(file_size, 3)} MB")
lbl_percent = Label(lbl_fr, text="0 %")
lbl_cancel_btn = ttk.Button(lbl_fr, image=cancel_btn_icon)
lbl_see_more = Label(second_frame, text="See more", fg="grey", font=("Arial", 10))
download_prg.grid(row=0, column=0, columnspan=2)
lbl_speed.grid(row=0, column=2, padx=5)
lbl_crnt_size.grid(row=1, column=1)
lbl_file_size.grid(row=1, column=0)
lbl_percent.grid(row=1, column=2)
lbl_cancel_btn.grid(row=0, column=3, rowspan=2)
lbl_fr.grid(row=times_clicked, column=0, padx=5, pady=5)
lbl_see_more.grid(row=times_clicked, column=1, padx=3)
times_clicked += 1
start_time = time.time()
while True:
if file_dir.exists():
time.sleep(0.5)
crnt_size = file_dir.stat().st_size / 1000000
size_eachsec = np.append(size_eachsec, crnt_size)
percent = (crnt_size / file_size) * 100
crnt_speed = size_eachsec[1] - size_eachsec[0]
size_eachsec = np.delete(size_eachsec, 0)
lbl_speed.config(text=f"{round(crnt_speed, 2)} MB/s")
lbl_crnt_size.config(text=f"Downloaded: {round(crnt_size, 3)} MB")
lbl_percent.config(text=f"{round(percent, 2)} %")
download_prg["value"] = percent
# print( f"Current Size: {crnt_size}, Current speed: {crnt_speed}, File size: {file_size},
# Percentage: {percent}% " f", Progress bar: {download_prg['value']}%")
if crnt_size == file_size:
break
end_time = time.time()
time_elapsed = end_time - start_time
print(f"Start time: {start_time}, End time: {end_time}, Time took: {time_elapsed}")
download_prg.config(cursor="arrow")
lbl_speed.config(text="Completed!")
def show_info(event):
global info_window
if info_window is not None and info_window.winfo_exists():
info_window.focus_set()
lbl_see_more.config(fg="purple")
else:
lbl_see_more.config(fg="purple")
info_window = Toplevel()
info_window.resizable(0, 0)
lbl_time_took = Label(info_window, text=f"Time elapsed: {round(time_elapsed, 2)}")
lbl_avg_speed = Label(info_window, text=f"Average speed: {round(file_size / time_elapsed, 3)} MB/s")
lbl_time_took.pack(pady=20)
lbl_avg_speed.pack(pady=20)
lbl_see_more.bind("<Button-1>", show_info)
new_font = font.Font(lbl_see_more, lbl_see_more.cget("font"))
new_font.configure(size=10, underline=True)
lbl_see_more.config(font=new_font, fg="blue", cursor="hand2")
print("Download successful! ")
def download_files(status_bar, url_entry, output_entry, name_entry, format_entry, num, chum, var):
global files_downloading
files_downloading += 1
status_bar.config(text=f"Downloading {files_downloading} file(s)...")
url = str(url_entry.get())
if num.get() == 1:
name = url.split("/")[-1].split(".")[0]
else:
name = str(name_entry.get())
formatname = str(format_entry.get())
if var.get() == 1:
operator = str(url_entry.get())
formatname = '.' + operator[-3] + operator[-2] + operator[-1]
else:
pass
static_fullname = str(name) + formatname
new_fullname = static_fullname
path = (str(output_entry.get()) + "/").replace(" \ ".strip(), "/")
if chum.get() == 1:
conn = sqlite3.connect("DEF_PATH.db")
c = conn.cursor()
c.execute("SELECT * FROM DIRECTORY_LIST WHERE SELECTED_DEF = 1")
crnt_default_path = c.fetchall()
# print(crnt_default_path)
path = str(crnt_default_path[0][0] + "/").replace(" \ ".strip(), "/")
conn.commit()
conn.close()
else:
pass
if path + static_fullname not in dir_files.keys():
dir_files[path + static_fullname] = 0
all_files_dir = os.listdir(path)
# if fullname in all_files_dir:
while new_fullname in all_files_dir:
dir_files[path + static_fullname] += 1
if num.get() == 1:
name = url.split("/")[-1].split(".")[0] + f" ({dir_files.get(path + static_fullname)})"
else:
name = str(name_entry.get()) + f" ({dir_files.get(path + static_fullname)})"
new_fullname = name + formatname
else:
pass
print(dir_files)
Process(target=get_info, args=(path, new_fullname, url_entry)).start()
urllib.request.urlretrieve(url, path + new_fullname)
if len(new_fullname) > 20:
toast.show_toast(title="8-bit Downloader",
msg=f"{new_fullname[:21] + '...'} was successfully downloaded. to '{path}'"
, duration=6, threaded=True)
else:
toast.show_toast(title="8-bit Downloader", msg=f"{new_fullname} was successfully downloaded. to '{path}'"
, duration=6, threaded=True)
files_downloading -= 1
status_bar.config(text=f"Downloading {files_downloading} file(s)...")
if files_downloading == 0:
status_bar.config(text="Download(s) successful!")
if __name__ == '__main__':
root = Tk()
tabs = ttk.Notebook()
# the top menu
num = IntVar()
chum = IntVar()
var = IntVar()
toast = win10toast.ToastNotifier()
def start_download():
Process(target=download_files,
args=(status_bar, url_entry, output_entry, name_entry, format_entry, num, chum, var),
daemon=True).start()
# the status bar
status_bar = Label(main_window, text="Awaiting download...", bd=1, relief=SUNKEN, anchor=W)
status_bar.pack(side=BOTTOM, fill=X)
# the download frame
body_frame = Frame(main_window, bg="light blue")
download_button = ttk.Button(body_frame, text="Download! ", command=start_download, padding=40, style='my.TButton')
download_button_tip = CreateToolTip(download_button, "Initiates the downloading process. ")
download_button.pack(side=LEFT, pady=5, padx=5)
body_frame.pack(side=LEFT, fill=Y)
def clear_entry(entryname, variable=None):
if variable is not None:
variable.set(0)
entryname.config(state=NORMAL)
entryname.delete(0, END)
if entryname is format_entry:
entryname.insert(0, '.')
# the main interaction menu
inter_frame = Frame(main_window)
trash_icon = ImageTk.PhotoImage(Image.open("icons/Asset 6.png"))
settings_icon = ImageTk.PhotoImage(Image.open("icons/Settings-icon.png"))
add_icon = ImageTk.PhotoImage(Image.open("icons/Plus-icon-8.png"))
minus_icon = ImageTk.PhotoImage(Image.open("icons/Minus-icon-8.png"))
change_path_icon = ImageTk.PhotoImage(Image.open("icons/Change-icon-8.png"))
url_entry = ttk.Entry(inter_frame, width=30)
label = ttk.Label(inter_frame, text="Enter the image URL: ")
clr_url = ttk.Button(inter_frame, image=trash_icon, command=lambda: clear_entry(url_entry))
file_format = ttk.Label(inter_frame, text="Choose your file format: ")
format_entry = ttk.Entry(inter_frame, width=30)
clr_format = ttk.Button(inter_frame, image=trash_icon, command=lambda: clear_entry(format_entry, var))
file_name = ttk.Label(inter_frame, text="File's name: ")
name_entry = ttk.Entry(inter_frame, width=30)
clr_name = ttk.Button(inter_frame, image=trash_icon, command=lambda: clear_entry(name_entry, num))
check_name_manual = ttk.Radiobutton(inter_frame, text="Enter name manually", variable=num,
value=0, command=lambda: name_entry.config(state=NORMAL))
check_name_auto = ttk.Radiobutton(inter_frame, text="Download with default name", variable=num,
value=1, command=lambda: name_entry.config(state=DISABLED))
check_format_manual = ttk.Radiobutton(inter_frame, text="Enter format manually", variable=var,
value=0, command=lambda: format_entry.config(state=NORMAL))
check_format_auto = ttk.Radiobutton(inter_frame, text="Download with default format", variable=var,
value=1, command=lambda: format_entry.config(state=DISABLED))
output_path = ttk.Label(inter_frame, text="Choose output path: ")
output_entry = ttk.Entry(inter_frame, width=30)
def set_path():
directory = filedialog.askdirectory(initialdir="/Downloads", title="Choose path")
if directory:
output_entry.delete(0, END)
output_entry.insert(0, directory)
select_path_btn = ttk.Button(inter_frame, width=3, text="...", command=set_path)
select_path_btn_tip = CreateToolTip(select_path_btn, "Pops up a filedialog to change directory. ")
default_path_btn = ttk.Button(inter_frame, image=settings_icon, command=None)
check_default_manual = ttk.Radiobutton(inter_frame, text="Enter path manually", variable=chum,
value=0, command=lambda: output_entry.config(state=NORMAL))
check_default_auto = ttk.Radiobutton(inter_frame, text="Download to default path", variable=chum,
value=1, command=lambda: output_entry.config(state=DISABLED))
file_name.grid(row=0, column=0, pady=(15, 10))
name_entry.grid(row=0, column=1, pady=(15, 10))
clr_name.grid(row=0, column=2, pady=(5, 0))
check_name_manual.grid(row=1, column=0, padx=(10, 0))
check_name_auto.grid(row=1, column=1, padx=(10, 0))
label.grid(row=2, column=0, pady=10, padx=(10, 0))
url_entry.grid(row=2, column=1, pady=10, padx=(10, 0))
clr_url.grid(row=2, column=2)
file_format.grid(row=3, column=0, pady=10, padx=(10, 0))
format_entry.grid(row=3, column=1, pady=10, padx=(10, 0))
format_entry.insert(0, '.')
clr_format.grid(row=3, column=2)
check_format_manual.grid(row=4, column=0, padx=(10, 0))
check_format_auto.grid(row=4, column=1, padx=(10, 0))
output_path.grid(row=5, column=0, pady=10, padx=(10, 0))
output_entry.grid(row=5, column=1, padx=(10, 5))
select_path_btn.grid(row=5, column=2)
check_default_manual.grid(row=6, column=0, pady=(0, 10), padx=(10, 0))
check_default_auto.grid(row=6, column=1, pady=(0, 10), padx=(10, 0))
default_path_btn.grid(row=6, column=2, pady=(0, 5))
inter_frame.pack(expand=1)
main_window.pack(fill="both", expand=1)
# The Downloads tab (this part is irrelevant so I wouldn't bother checking this part out just put it there in case)
lbl_await = ttk.Label(download_fr, text="Awaiting Download...", font=("Helvetica", 24))
prg_br = ttk.Progressbar(download_fr, orient=HORIZONTAL, length=250, mode='indeterminate')
my_canvas = Canvas(download_fr)
my_scrollbar = ttk.Scrollbar(download_fr, orient=VERTICAL, command=my_canvas.yview)
my_canvas.configure(yscrollcommand=my_scrollbar.set)
lbl_await.pack(pady=(85, 8))
prg_br.pack()
prg_br.start(6)
my_canvas.pack(side=LEFT, fill=BOTH, expand=1)
download_fr.pack(fill="both", expand=1)
second_frame = Frame(my_canvas)
# Add that new frame to a window in the canvas
my_canvas.create_window(0, 0, window=second_frame, anchor='nw')
# update canvas scrollregion whenever the size of second_frame is changed
second_frame.bind('<Configure>', lambda e: my_canvas.configure(scrollregion=my_canvas.bbox('all')))
tabs.pack(fill="both")
tabs.add(main_window, text="Main Window")
tabs.add(download_fr, text="Downloads")
root.mainloop()
# the end!