[pygtk] progressbar for file managing

[John Dennis]

On Mon, 2007-04-16 at 19:55 +0000, Fabian Braennstroem wrote:
> Hi,
> 
> I would like to add a progressbar for file managing such as copying,
> deleting, moving. Unfortunately I don't understand the handling of
> the progressbar...
> As a first try I would like to use the 'pulse' function for the
> progressbar, i.e. as long as I copying files I would like to 'pulse'
> the bar. Below you can see a small example; I get the progressbar
> moving, but not during the copying process :-(
> 
> #!/usr/bin/env python
> 
> 
> import pygtk
> pygtk.require('2.0')
> import gtk
> import shutil
> from time import sleep
> 
> 
> file1="/home/fab/.bashrc"
> 
> class Buttons:
>     def callback(self, widget, data=None):
>         i=0
>         n=100
> 
>         self.progress.pulse()
>         self.progress.set_text("Calculating....")
>         self.progress.grab_add()
> 
>         shutil.copy(file1,"progressbar_copy")
>         while i < n:
>             sleep(0.015)
> #            self.progress.set_fraction(i/(n - 1.0))
>             self.progress.pulse()
>             i += 1
> 
>             while gtk.events_pending():
>                 gtk.main_iteration_do(False)
> 
>         self.progress.set_fraction(0.0)
>         self.progress.set_text("")
>         self.progress.grab_remove()
> 
>     def __init__(self):
>         self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
> 
>         self.window.connect("destroy", lambda wid: gtk.main_quit())
>         self.window.connect("delete_event", lambda
> a1,a2:gtk.main_quit())
>         self.window.set_border_width(10)
>         box = gtk.HBox()
> 
>         self.progress= gtk.ProgressBar()
>         button = gtk.Button("Button")
>         button.connect("clicked", self.callback, "cool button")
> 
>         button.show()
>         self.progress.show()
>         box.add(self.progress)
>         box.add(button)
>         box.show()
> 
> 
>         self.window.add(box)
>         self.window.show()
> 
> def main():
>     gtk.main()
>     return 0
> 
> if __name__ == "__main__":
>     Buttons()
>     main()
> 
> 
> A next step would be, to display the remaing bytes and percentage of
> the copied file until completion (like the midnight commander is
> doing). How can I achive this? The progressbar has to know the size
> and the actual copied/moved/deleted number of bytes... Does anyone
> has an idea? Would be nice ...
> 
> I am doing the file managing with 'shutil' or 'os' modules.

Your basic problem is you're trying to code what is essentially a
parallel operation in a synchronous manner. To move the progress bar you
have to call the functions to move it (e.g. pulse or set_fraction), but
you can't do that if you're waiting on a synchronous operation to
complete (or worse calling sleep). You have a few choices, either do the
copy yourself in a loop where you copy chunks of data and update the
progress bar, find an API which does the copy in a thread and provide
progress callbacks (sorry I'm not aware of such an API), or do the
threading yourself. FWIW, here is a code snippet of mine, it installs a
timeout function to pulse the progress bar every 1/10 sec until the
operation completes. The trick here is that the operation is being
handled in another thread so it proceeds independently of the the GUI
thread.

    def progress_pulse(self):
        if self.load_in_progress:
            self.statusbar.progress.pulse()
            return True                 # call again
        else:
            return False                # do not call again

    def on_load_data(self, list_view, alert_data, state, errno, strerror):
        if state == 'start':
            self.load_in_progress = True
            self.statusbar.progress.pulse()
            gobject.timeout_add(100, self.progress_pulse)

> Greetings!
> Fabian
> 
> _______________________________________________
> pygtk mailing list   pygtk at daa.com.au
> http://www.daa.com.au/mailman/listinfo/pygtk
> Read the PyGTK FAQ: http://www.async.com.br/faq/pygtk/
-- 
John Dennis <jdennis at redhat.com>