ttk进度条冻结 [英] ttk progress bar freezing

问题描述

我想要一个向用户显示下载进度的进度条.更新GUI并同时下载时，进度条冻结，我明白为什么，但我不知道如何解决.我使用这篇文章尝试了多线程:Tkinter:如何使用线程来防止来自冻结" 和使用 Python 基础知识的主事件循环多线程和队列作为帮助我满足我需求的指南.问题是，我尝试以哪种方式实现目标，但在更改它以执行我需要它做的事情时似乎总是犯错误.

I want a progress bar that shows the user the download progress. When updating the GUI and downloading at the same time the progress bar freezes, and I understand why but I don't know how to solve it. I tried multithreading using this post: Tkinter: How to use threads to preventing main event loop from "freezing" and using The Basics of Python Multithreading and Queues as a guid to help me fit it to my needs. The problem is that which way I try to achieve my goal, I always seem to make a mistake when changing it to do what I need it to do.

我的代码的最基本版本(没有多线程):

The most basic version of my code (without multithreading):

from Tkinter import *
import ttk
from urllib import URLopener # Downloading files 

# Make frame to tell user what file is getting downloaded
self.Progressmsg = Label(self, text="TempValue")
self.Progressmsg.pack(pady=(10,0))

# Make progress bar to show user download progress
self.Progressbar = ttk.Progressbar(self, mode="determinate", orient='horizontal', lengt=280, maximum=len(self.AllClasses))
self.Progressbar.pack(padx=10, pady=10)
self.Progressbar["value"] = 0

def DownloadFile(Class):
    # Update progress message
    self.Progressmsg["text"] = "Downloading {0}.ics...".format(Class)

    # Download each file from saxion website
    CalFile = URLopener()
    CalFile.retrieve("http://[school website]/ical/group/{0}.ics".format(Class), "Data/{0}.ics".format(Class))

    # Update progress bar
    self.Progressbar["value"] += 1

for Study in self.Parameters["Classes"]:
    for Class in Study:
        DownloadFile(Class)

注意:在这段代码中，AllClasses 是一个不同类的列表，日历文件必须从这些类中下载.
代码本身是我没有包含的相当大的类的一部分.这就是为什么我使用 self.[variablename]

Notes: In this code AllClasses is a list of different classes from which a calendar file has to be downloaded.
The code itself is part of a fairly large class which I didn't include. This is why I am using self.[variablename]

当此代码运行时，进度条不会加载或更新，所有文件都会正确下载，下载时进度条会立即更新所有内容.我的问题是:我该如何解决这个问题?

When this code runs the progressbar doesn't load or update, all the files download properly and when they are downloaded the progress bar updates everything at once. My question is: how do I solve this problem in my case?

推荐答案

试试这个:

# Update progress bar
self.Progressbar["value"] += 1
self.Progressbar.update_idletasks()

如果它不起作用，则使用 self.Progressbar.update() 代替.

If it does not work then use self.Progressbar.update() instead.

除非您调用 update_idletasks() 或 update()，否则如果有其他事情要做(例如下载下一个文件)，GUI 将不会反映您的更改.

The GUI won't reflect your changes if there is something else to do (like downloading the next file) unless you call update_idletasks() or update().

这篇关于ttk进度条冻结的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！