tkinter-progressbar用于多处理

Question

我有一个加密文件的程序，我使用了多处理来加快速度，但我在tkinter进度条方面遇到了问题。

我已经实现了它，但它立即完成或滞后于两者。进度条刚刚完成到100%，但文件仍在加密，我没有收到任何错误。

files包含文件列表。

整个代码在这里-https://codeshare.io/pq8YxE

以下是我实现它的方式。

def progbar():
global pb_lable
global percent
global pbar
global percentlabel
global pbar_frame

pb_lable = tk.Label(root, text='Progress', font = "Raleway 13 bold")
pb_lable.grid(row=5, columnspan=2, sticky='w', padx=(35))
pbar_frame = tk.Frame(root)
pbar_frame.grid(row=6, columnspan=2)
pbar = Progressbar(pbar_frame,orient='horizontal',length=500,mode='determinate')
pbar.grid(row=7,column=0, pady=10, padx=20)
percent = tk.StringVar()
percentlabel = tk.Label(root, textvariable=percent, font='Raleway 15')
percentlabel.grid(row=5,columnspan=2,pady=10, padx=120, sticky='w')

def encryptfn(key, a):
f = Fernet(key)
return f.encrypt(a)
def enc(key, process_pool, file):
task = len(files)
x = 0
with open(file,'rb') as original_file:
original = original_file.read()
encrypted = process_pool.apply(encryptfn, args=(key, original,))
with open (file,'wb') as encrypted_file:
encrypted_file.write(encrypted)

pbar['value']+=100/task
x = x+1
percent.set(str(int((x/task)*100))+'%')
root.update_idletasks()
def encfile():
password = bytes('asdasd', 'utf-8')
salt = bytes('zxcasd','utf-8')
global files
files = filistbox.get(0,'end')
if len(files) == 0:
fierrorbox()
elif len(password) == 0:
passerrorbox()
else:
file_enc_button['state']='disabled'
browsefi['state']='disabled'
kdf = PBKDF2HMAC(
algorithm=hashes.SHA256(),
length=32,
salt=salt,
iterations=100,
backend=default_backend())
key = base64.urlsafe_b64encode(kdf.derive(password))
MAX_THREADS = 300
pool_size = min(MAX_THREADS, cpu_count(), len(files))
process_pool = Pool(pool_size)
thread_pool = ThreadPool(min(MAX_THREADS, len(files)))
worker = partial(enc, key, process_pool)
thread_pool.map(worker, files)
root.event_generate("<<encryption_done>>")

file_enc_button['state']='active'
browsefi['state']='active'
def run_encfile():
root.bind('<<encryption_done>>', encryption_done)
Thread(target=encfile).start()
def encryption_done(*args):
fiencdone()
if __name__ == '__main__':
root = tk.Tk()
browsefi = tk.Button(root, text='Browse', command=fibrowse, borderwidth=3)
browsefi.grid(row=2,column=0,padx=5, pady=5)
##  File list  ##
filist_frame = tk.Frame(root)
filist_frame.grid(row=3, columnspan=2)
filistbox = tk.Listbox(filist_frame, width=40, height=10)
filistbox.grid(row=3,columnspan=2, pady=10)
## Button ##
fibutton_frame = tk.Frame(root)
fibutton_frame.grid(row=4, columnspan=2)
file_enc_button = tk.Button(fibutton_frame, text='Encrypt', width=15, command=run_encfile, borderwidth=3)
file_enc_button.grid(row=4,column=0,padx=10,pady=15)
progbar()
percent.set('0%')
root.mainloop()

Answer 1

函数enc出现问题，您一直在将变量x重置回0。

您需要一个全局变量，例如初始化为0的tasks_completed，它跟踪已完成的加密次数，并在enc中使用语句tasks_completed += 1递增。从技术上讲，这等效于tasks_completed = tasks_completed + 1，并且不是原子操作，并且理论上线程可能在读取tasks_completed的值之后被中断，因此两个线程将把tasks_completed更新为相同的值。因此，为了完全安全，这个更新应该在multithreading.Lock的控制下进行，以确保一次只有一个线程可以进行更新。

将功能enc替换为：

from threading import Lock
tasks_completed = 0
def enc(key, process_pool, lock, file):
global tasks_completed
with open(file,'rb') as original_file:
original = original_file.read()
encrypted = process_pool.apply(encryptfn, args=(key, original,))
with open (file,'wb') as encrypted_file:
encrypted_file.write(encrypted)
encrypted = process_pool.apply(encryptfn, args=(key, file,))
with lock:
tasks_completed += 1
percentage_completed = int((tasks_completed / len(files)) * 100)
pbar['value'] = percentage_completed
percent.set(f'{percentage_completed}%')
root.update_idletasks()

并创建一个multiprocessing.Lock实例，并通过如下修改函数将其传递给函数encfile中的enc：

lock = Lock() # create lock
# add additional lock argument to enc:
worker = partial(enc, key, process_pool, lock)