更新 Tkinter 列表框的更好方法
你好 所以首先我制作了一个程序来下载音乐并在列表框中显示已下载的百分比。
有点像这样，
from Tkinter import *
from urllib2 import *
admin = Tk()
Admin = Tk()
listbox = Listbox(admin, bg="PURPLE")
listbox.pack()
def fores():
chunks = 10000
dat = ''
song = '3 rounds and a sound'
url = 'http://bonton.sweetdarkness.net/music/Blind%20Pilot%20--%203%20Rounds%20and%20A%20Sound.mp3'
down = urlopen(url)
downso = 0
tota = down.info().getheader('Content-Length').strip()
tota = int(tota)
while 1:
a = down.read(chunks)
downso += len(a)
if not a:
break
dat += a
percent = float(downso) / tota
percent = round(percent*100, 1)
listbox.insert(END, percent)
listbox.update()
listbox.delete(0, END)
listbox.insert(END, percent)
listbox.update()
button = Button(Admin, text='Download', command=fores)
button.pack()
button = Button(Admin, text='Download', command=fores)
button.pack()
mainloop()
我不会向您展示原始程序，因为它超出了帖子大小的限制。
在我原来的程序中，如果我在下载 mp3 文件之前移动窗口，它会下载不到 3% 并停止，如果我关闭窗口，它会再次开始下载。
有谁知道这是为什么，或者是否有其他方法可以在 Tkinter 窗口上显示百分比？ 请帮忙
，update_idletasks 不起作用
Hi
so first of all i made a program that downloads music and displays the percent that has downloaded in a list box.
kind of like this
from Tkinter import *
from urllib2 import *
admin = Tk()
Admin = Tk()
listbox = Listbox(admin, bg="PURPLE")
listbox.pack()
def fores():
chunks = 10000
dat = ''
song = '3 rounds and a sound'
url = 'http://bonton.sweetdarkness.net/music/Blind%20Pilot%20--%203%20Rounds%20and%20A%20Sound.mp3'
down = urlopen(url)
downso = 0
tota = down.info().getheader('Content-Length').strip()
tota = int(tota)
while 1:
a = down.read(chunks)
downso += len(a)
if not a:
break
dat += a
percent = float(downso) / tota
percent = round(percent*100, 1)
listbox.insert(END, percent)
listbox.update()
listbox.delete(0, END)
listbox.insert(END, percent)
listbox.update()
button = Button(Admin, text='Download', command=fores)
button.pack()
button = Button(Admin, text='Download', command=fores)
button.pack()
mainloop()
I wont show you the original program for it is over the limit of the post size.
On my original program if i move the window before i download an mp3 file it downloads less then 3 % and stops and if i then close the window it starts downloading again.
does anyone know why this is or if there is an alternative to displaying the percentage on the Tkinter window?
Please help
and update_idletasks doesent work
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用于显示字符串的正确小部件是 标签。您可以使用
configure方法在运行时更改文本：其次，您将创建两个根窗口 -
admin和Admin。奇怪的是，您将列表框放在一个列表框中，而将按钮放在另一个中。 Tk 的设计初衷并非如此。第三，您需要调用（单个）根窗口的 mainloop 方法（例如：Admin.mainloop）最后，关于您的评论，
update_idletasks不起作用 - - 请定义“不起作用”。它实际上会更新显示。它不会让您在窗口运行时与窗口交互。我根据上述注释对您的代码进行了更改（仅创建一个根，使用
Label而不是Listbox，并使用update_idletasks和程序运行完成，下载歌曲。调用
update的危险是：如果您在下载时单击“下载”按钮，那么下次update< 时会发生什么？ 无限循环，而外部循环将无法运行。/code> 被调用，在该事件的服务中，您将进入一个 正确的解决方案涉及（至少）两种技术之一。一是创建一个线程来执行下载，并让它定期将信息发送回主循环，以便它可以更新进度条。二是利用现有的无限。循环——事件循环——通过使用
after将作业放入事件队列来一次读取一个块。互联网上有这两种方法的示例。
The proper widget for displaying a string is a Label. You can change the text at runtime with the
configuremethod:Second, you are creating two root windows -
adminandAdmin. And strangely, you are putting the listbox in one and the buttons in another. Tk isn't designed to work like that. Third, you need to call the mainloop method of your (single) root window (eg:Admin.mainloop)Finally, as to your comment that
update_idletasksdoesn't work -- please define "doesn't work". It will in fact update the display. What it won't do is let you interact with the window while it is running.I made changes to your code based on the above comments (created only one root, used a
Labelrather thanListbox, and usedupdate_idletasksand the program ran to completion, downloading the song.The danger of calling
updateis this: what if you click the "download" button while you are already downloading? What happens is the next timeupdateis called, that button press will be serviced. In the servicing of that event you'll enter an infinite loop. While that inner infinite loop is running the outer one cannot run. You will have effectively frozen the first download.The proper solution involves one of (at least) two techniques. One, create a thread to do the downloading, and have it periodically send information back to the main loop so it can update the progress bar. The second is to leverage the already existing infinite loop -- the event loop -- and do your reading of chunks one at a time by placing jobs on the event queue with
after.There are examples on the internet for both approaches.
我使用 ttk.Progressbar，您所要做的就是将一个变量与其关联并更新该特定变量。
http://docs.python.org/library/ttk.html#progressbar
http://www.tkdocs.com/tutorial/morewidgets.html#progressbar
i use a ttk.Progressbar, all you have to do is associate a variable to it and update that particular variable.
http://docs.python.org/library/ttk.html#progressbar
http://www.tkdocs.com/tutorial/morewidgets.html#progressbar