Python / Glade / PyGTK - 下载Glade标签中的百分比

Question

I'm trying to setup a little download application using Glade, PyGTK, and Python. I have it planned how I'd like to script this progress bar and all, though I feel I'm going about it the wrong way as... Well... It's not working.

I'm using a little script I found for a checking the percentage of a download and then usually it would print to terminal, but instead I'd like it alter a label in Glade. Though, instead of the label changing when as the download progresses, the GUI freezes until the file is done and THEN updates saying it's 100% complete.

What would be the best method about making something like this work? Any help is appreciated, thanks in advance!

Python Script:

import sys
import pygtk
pygtk.require("2.0")
import gtk
import gtk.glade
import urllib2
import time

class FileSelector:

    def __init__(self):

        #Set the Glade file
        filename = "FileSelector.glade"
        self.builder = gtk.Builder()
        self.builder.add_from_file(filename)
        self.builder.connect_signals(self)
        self.window = self.builder.get_object("MainWindow")
        self.label1 = self.builder.get_object("label1")

    def on_MainWindow_destroy(self, obj):
        gtk.main_quit() #make the program quit


    def btnSubmit_clicked(self, widget):
        status_dropbox = self.builder.get_object("chkboxDropbox")
        status_python = self.builder.get_object("chkboxPython")
        status_chrome = self.builder.get_object("chkboxChrome")

        #Start downloader script
        url = "http://dl.dropbox.com/u/9235267/project.png"

        file_name = url.split('/')[-1]
        u = urllib2.urlopen(url)
        f = open(file_name, 'wb')
        meta = u.info()
        file_size = int(meta.getheaders("Content-Length")[0])
        print "Downloading: %s Bytes: %s" % (file_name, file_size)

        file_size_dl = 0
        block_sz = 8192
        while True:
            buffer = u.read(block_sz)
            if not buffer:
               break

            file_size_dl += len(buffer)
            f.write(buffer)
            status = r"%10d  [%3.2f%%]" % (file_size_dl, file_size_dl * 100. / file_size)
            self.label1.set_text(status)

        f.close()


if __name__ == "__main__":
    FileSelector()
    gtk.main()

Glade File (FileSelector.glade):

<?xml version="1.0" encoding="UTF-8"?>
<interface>
  <requires lib="gtk+" version="2.24"/>
  <!-- interface-naming-policy project-wide -->
  <object class="GtkWindow" id="MainWindow">
    <property name="visible">True</property>
    <property name="can_focus">False</property>
    <property name="title" translatable="yes">MainWindow</property>
    <property name="resizable">False</property>
    <property name="window_position">center</property>
    <signal name="destroy" handler="on_MainWindow_destroy" swapped="no"/>
    <child>
      <object class="GtkVBox" id="vbox1">
        <property name="visible">True</property>
        <property name="can_focus">False</property>
        <child>
          <object class="GtkLabel" id="label1">
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="label" translatable="yes">Enviroment Downloader</property>
            <attributes>
              <attribute name="style" value="normal"/>
              <attribute name="size" value="300"/>
            </attributes>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <object class="GtkCheckButton" id="chkboxDropbox">
            <property name="label" translatable="yes">Dropbox</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="receives_default">False</property>
            <property name="use_action_appearance">False</property>
            <property name="draw_indicator">True</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">1</property>
          </packing>
        </child>
        <child>
          <object class="GtkCheckButton" id="chkboxPython">
            <property name="label" translatable="yes">Python</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="receives_default">False</property>
            <property name="use_action_appearance">False</property>
            <property name="draw_indicator">True</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">2</property>
          </packing>
        </child>
        <child>
          <object class="GtkCheckButton" id="chkboxChrome">
            <property name="label" translatable="yes">Google Chrome</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="receives_default">False</property>
            <property name="use_action_appearance">False</property>
            <property name="draw_indicator">True</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">3</property>
          </packing>
        </child>
        <child>
          <object class="GtkButton" id="btnSubmit">
            <property name="label" translatable="yes">Download/Run</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="receives_default">True</property>
            <property name="use_action_appearance">False</property>
            <signal name="clicked" handler="btnSubmit_clicked" swapped="no"/>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">4</property>
          </packing>
        </child>
      </object>
    </child>
  </object>
</interface>

Answer 1

After the line

self.label1.set_text(status)

Add:

while gtk.events_pending():
    gtk.main_iteration()

This will update the GUI and run the main loop while you are waiting for the file to download, and you won't have to use threads.

Answer 2

You will need to use threads for this. If you are downloading in the callback function then the eventing is blocked on the button & you can see that the button is in pressed state ie it is waiting for the callback function to complete and return. Although my knowledge of python is nil, I could cook up some sample as follows using google etc:

import sys
import pygtk
pygtk.require("2.0")
import gtk
import gtk.glade
import urllib2
import time
import threading
import glib

# Replace this with what you want to do
def download(label):
        index = 0
        while True:
            if index>1200:
               break
        index += 120
        time.sleep(1)
        status = r"%10d " % (index)
        label.set_label(status)

class FileSelector:

    def __init__(self):

        #Set the Glade file
        filename = "FileSelector.glade"
        self.builder = gtk.Builder()
        self.builder.add_from_file(filename)
        self.builder.connect_signals(self)
        self.window = self.builder.get_object("MainWindow")
        self.label1 = self.builder.get_object("label1")

    def on_MainWindow_destroy(self, obj):
        gtk.main_quit() #make the program quit


    def btnSubmit_clicked(self, widget):
        status_dropbox = self.builder.get_object("chkboxDropbox")
        status_python = self.builder.get_object("chkboxPython")
        status_chrome = self.builder.get_object("chkboxChrome")
# Launch the thread to update label
        threading.Thread(target=download, args=(self.builder.get_object("label1"),)).start()

if __name__ == "__main__":
    FileSelector()
    glib.threads_init()
# Add gdk thread enter and leave
    gtk.main()

You can refer this question as well.
Hope this helps!
PS: Add thread safety & maybe disable button till download is complete?