Labels not updating its display data

Is it possible to display and update data using labels in a window, created by another window?

This is a program I did that is not working as expected:

I'm creating a second window inside of a function call newcount. This other window even have separate
variables, but if I use the label type of display, that data is not show, and even less chage its value.

Can somebody tell me if it's possible to do what I'm trying? How can I display a value inside of a label, and
have that display update its values, when this is trying to be done in a second window.

Guido

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Re: Labels not updating its display data

Hi Guido,

On Thu, 01 Apr 2010 00:02:36 -0600
Guido Carballo-Guerrero <charras <at> me.com> wrote:

> Is it possible to display and update data using labels in a window,
> created by another window?
> 
> This is a program I did that is not working as expected:
> 
> 
(...)
> def newcount():
> 
>     root2 = Tkt.Tk()
>     var2 = Tkt.IntVar()
>     frameLabels2 = Tkt.Frame(root2)
>     frameLabels2.pack()
> 
>     def changeVal():
> 
>         var2.set(var2.get()+1)
>         print 'var2: ',var2.get()
>         
> 
>     Tkt.Label(frameLabels2,text='var2: ').pack(side=Tkt.LEFT)
>     Tkt.Label(frameLabels2,textvariable=var1).pack(side=Tkt.LEFT)
>     
>     Tkt.Button(root2,text="Change value", command=changeVal).pack()
>     root2.mainloop()

macPython, menubar won't display, new windows will not display widgets

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Re: Tkinter-discuss Digest, Vol 74, Issue 2

Michael;

Thank you very much. I'm kinda new to Python and Tkinter, and didn't know anything about Toplevel, that was
exactly what I need.

But tell me, why I can't use two instances of Tk? The way I saw this, was that I was just creating a new object, so
I don't understand what is the problem in creating a second object of Tk. I know it doesn't work, but I will
like to understand why.

If you don't know the answer, don't mind. Thank you very much anyway. You really help me on this one.

Charras

On Apr 2, 2010, at 4:00 AM, tkinter-discuss-request <at> python.org wrote:

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>   1. Re: Labels not updating its display data (Michael Lange)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Thu, 1 Apr 2010 12:27:12 +0200
> From: Michael Lange <klappnase <at> web.de>
> To: tkinter-discuss <at> python.org
> Subject: Re: [Tkinter-discuss] Labels not updating its display data
> Message-ID: <20100401122712.60670f79.klappnase <at> web.de>
> Content-Type: text/plain; charset=US-ASCII
> 
> Hi Guido,
> 
> On Thu, 01 Apr 2010 00:02:36 -0600
> Guido Carballo-Guerrero <charras <at> me.com> wrote:
> 
>> Is it possible to display and update data using labels in a window,
>> created by another window?
>> 
>> This is a program I did that is not working as expected:
>> 
>> 
> (...)
>> def newcount():
>> 
>>    root2 = Tkt.Tk()
>>    var2 = Tkt.IntVar()
>>    frameLabels2 = Tkt.Frame(root2)
>>    frameLabels2.pack()
>> 
>>    def changeVal():
>> 
>>        var2.set(var2.get()+1)
>>        print 'var2: ',var2.get()
>> 
>> 
>>    Tkt.Label(frameLabels2,text='var2: ').pack(side=Tkt.LEFT)
>>    Tkt.Label(frameLabels2,textvariable=var1).pack(side=Tkt.LEFT)
>> 
>>    Tkt.Button(root2,text="Change value", command=changeVal).pack()
>>    root2.mainloop()
> 
> There are two problems in this function, first you should _never_ use
> two instances of Tk() in one program; if you need a second window, use
> a Tkinter.Toplevel() instead.
> Second, you assign var1 as textvariable for the Label; I think what you
> actually intended is to set the current value of var1 as initial value
> for var2 and then use var2 as textvariable for the label ? If yes,
> simply change the first lines of newcount() into:
> 
> def newcount():
> 
>    root2 = Tkt.Toplevel()
>    var2 = Tkt.IntVar()
>    var2.set(var1.get())
> 
> I hope this helps
> 
> Michael
> 
> 
> 
> 
> 
> 
> ------------------------------
> 
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> Tkinter-discuss mailing list
> Tkinter-discuss <at> python.org
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> 
> 
> End of Tkinter-discuss Digest, Vol 74, Issue 2
> **********************************************

Re: Tkinter-discuss Digest, Vol 74, Issue 2

Hi Guido,

On Fri, 02 Apr 2010 12:32:03 -0600
Guido Carballo-Guerrero <charras <at> me.com> wrote:

> Michael;
> 
> Thank you very much. I'm kinda new to Python and Tkinter, and didn't
> know anything about Toplevel, that was exactly what I need.
> 
> But tell me, why I can't use two instances of Tk? The way I saw this,
> was that I was just creating a new object, so I don't understand what
> is the problem in creating a second object of Tk. I know it doesn't
> work, but I will like to understand why.
> 

I will try to explain, though I am not a no.1 expert :)

The Tk() window is not just a widget, like a Button or a Toplevel, but
has its own associated Tcl interpreter which is controlled through
Python; so if you have two Tk instances in your application, you have
two different Tcl interpreters running.
As you noticed in your first code example, this did work, but not
exactly as you expected. The reason is that the two Tcl interpreters
cause some unwanted side effects, because they can coexist, but not
interact; for example, (IIRC) you created two IntVars, but IntVar2
inside the second Tcl interpreter, which will not work when trying to
use it as textvariable for a Label belonging to Tcl interpreter #1 ; if
the application becomes more complex, it will obviously become hard to
avoid running into traps like this, when OTOH there is not really a
benefit from the second Tk() window.

I hope this helps

Michael

Re: Tkinter-discuss Digest, Vol 74, Issue 2

On Fri, Apr 02, 2010 at 09:02:15PM +0200, Michael Lange wrote:
			.
			.
			.
> > But tell me, why I can't use two instances of Tk? The way I saw this,
> > was that I was just creating a new object, so I don't understand what
> > is the problem in creating a second object of Tk. I know it doesn't
> > work, but I will like to understand why.
> > 
> 
> I will try to explain, though I am not a no.1 expert :)
> 
> The Tk() window is not just a widget, like a Button or a Toplevel, but
> has its own associated Tcl interpreter which is controlled through
> Python; so if you have two Tk instances in your application, you have
> two different Tcl interpreters running.
> As you noticed in your first code example, this did work, but not
> exactly as you expected. The reason is that the two Tcl interpreters
> cause some unwanted side effects, because they can coexist, but not
> interact; for example, (IIRC) you created two IntVars, but IntVar2
> inside the second Tcl interpreter, which will not work when trying to
> use it as textvariable for a Label belonging to Tcl interpreter #1 ; if
> the application becomes more complex, it will obviously become hard to
> avoid running into traps like this, when OTOH there is not really a
> benefit from the second Tk() window.
> 
> I hope this helps
			.
			.
			.
Worse, each Tk() instance opens a "graphical context", and
*their* behavior isn't well-defined beyond one-per-process.

background threading

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Re: background threading

On 4/6/10 5:03 PM, Nemes Andrei wrote:

>
> Another solution to the problem would be pointing me to a more
> convenient tray icon constructor (instructions how to use would be
> greatly appreciated) if you know any.
>
> I hope someone can help me. Thank you for your time and support.

This seems a rather convoluted way to do things. There are various Tk 
extensions that provide system tray functionality and it should be 
fairly simple to write a Python wrapper for them.

If you're on Windows, look at winico:

http://wiki.tcl.tk/4089

If you're on *Nix, look at tktray:

http://wiki.tcl.tk/5972

or freedock:

http://wiki.tcl.tk/4090

--Kevin

--

-- 
Kevin Walzer
Code by Kevin
http://www.codebykevin.com

Re: background threading

Hi,

On Tue, 06 Apr 2010 18:37:42 -0400
Kevin Walzer <kw <at> codebykevin.com> wrote:

> On 4/6/10 5:03 PM, Nemes Andrei wrote:
> 
> >
> > Another solution to the problem would be pointing me to a more
> > convenient tray icon constructor (instructions how to use would be
> > greatly appreciated) if you know any.
> >
> > I hope someone can help me. Thank you for your time and support.
> 
> This seems a rather convoluted way to do things. There are various Tk 
> extensions that provide system tray functionality and it should be 
> fairly simple to write a Python wrapper for them.
> 
> If you're on Windows, look at winico:
> 
> http://wiki.tcl.tk/4089
> 
> If you're on *Nix, look at tktray:
> 
> http://wiki.tcl.tk/5972
> 
> or freedock:
> 
> http://wiki.tcl.tk/4090
> 
> --Kevin
> 

If you want to use tktray, I already wrote a wrapper for it;
to create a tray icon, you can do something like:

root = Tk()
root.withdraw()
img = PhotoImage(file='image.gif')
icon = TkTray.Icon(root)
icon.configure(image=img)
icon.menu.add_command(label='Quit', command=root.quit)

HTH

Michael

######## file TkTray.py #####################################

import Tkinter

class Icon(Tkinter.BaseWidget, Tkinter.Wm):
    def __init__(self, master=None, cnf={}, **kw):

        if not master:
            if Tkinter._support_default_root:
                if not Tkinter._default_root:
                    Tkinter._default_root = Tkinter.Tk()
                master = Tkinter._default_root
        self.TktrayVersion = master.tk.call('package', 'require', 'tktray')

        # stolen from Tkinter.Toplevel
        if kw:
            cnf = Tkinter._cnfmerge((cnf, kw))
        extra = ()
        for wmkey in ['screen', 'class_', 'class', 'visible', 'colormap']:
            if cnf.has_key(wmkey):
                val = cnf[wmkey]
                # TBD: a hack needed because some keys
                # are not valid as keyword arguments
                if wmkey[-1] == '_': opt = '-'+wmkey[:-1]
                else: opt = '-'+wmkey
                extra = extra + (opt, val)
                del cnf[wmkey]
        Tkinter.BaseWidget.__init__(self, master, 'tktray::icon', cnf, {}, extra)
        self.protocol("WM_DELETE_WINDOW", self.destroy)

        self.menu = Tkinter.Menu(self, tearoff=0)
        self.bind('<3>', self._popupmenu)

    def bbox(self):
        return self._getints(self.tk.call(self._w, 'bbox')) or None

    def _popupmenu(self, event):
        w, h = self.menu.winfo_reqwidth(), self.menu.winfo_reqheight()
        x0, y0, x1, y1 = self.bbox()
        # get the coords for the popup menu; we want it to the mouse pointer's
        # left and above the pointer in case the taskbar is on the bottom of the
        # screen, else below the pointer; add 1 pixel towards the pointer in each
        # dimension, so the pointer is '*inside* the menu when the button is being
        # released, so the menu will not unpost on the initial button-release event
        if y0 > self.winfo_screenheight() / 2:
            # assume the panel is at the bottom of the screen
            x, y = event.x_root - w + 1, event.y_root - h + 1
        else:
            x, y = event.x_root - w + 1, event.y_root - 1
        # make sure that x is not outside the screen
        if x < 5:
            x = 5
        self.menu.tk_popup(x, y)

#################################################################

Re: background threading

Hi,

On Wed, 7 Apr 2010 08:00:38 -0700 (PDT)
Nemes Andrei <teh_sh_meister <at> yahoo.com> wrote:

> I'm sorry for being such a beginner in this, but could not find where
> to download the winico. Is it included in Tk already? 

I think you will have to download winico-0.6.zip from

    http://sourceforge.net/projects/tktable/files/

and copy the winico-0.6 folder into your Python's Tcl folder so that Tk
can find it. Unfortunately there does not seem to be a Tkinter wrapper
available, so you will have to write it yourself :(

>From a quick glance at the winico manpage a quick'n'dirty wrapper could
look like this (untested!):
############# file Winico.py ##############################
import Tkinter

class Winico:
    def __init__(self, filename):

        master = Tkinter._default_root
        if not master:
            raise RuntimeError, 'Too early to create icon'
        self.WinicoVersion = master.tk.call('package', 'require', 'winico')
        self.tk = master.tk

    def createfrom(self, filename):
        return self.tk.call('winico', 'createfrom', filename)

    def delete(self, id_):
        self.tk.call('winico', 'delete', id_)

    def load(self, resourcename, filename=None):
        return self.tk.call('winico', 'load', resourcename, filename)

    def info(self, id_=None):
        # the output should of course be formatted somehow
        return self.tk.call('winico', 'info', id_)

    def setwindow(self, size='big', pos=None):
        return self.tk.call('winico', 'setwindow', size, pos)

    def taskbar_add(self, id_, callback=None, pos=None, text=None):
        args = ()
        if callback:
            args += ('-callback', callback)
        if pos:
            args += ('-pos', pos)
        if text:
            args += ('-text', text)
        return self.tk.call('winico', 'taskbar', 'add', id_, *args)

    def taskbar_modify(self, id_, callback=None, pos=None, text=None):
        args = ()
        if callback:
            args += ('-callback', callback)
        if pos:
            args += ('-pos', pos)
        if text:
            args += ('-text', text)
        return self.tk.call('winico', 'taskbar', 'modify', id_, *args)

    def taskbar_delete(self, id_):
        return self.tk.call('winico', 'taskbar', 'delete', id_)

#########################################################

If you compare this with the winico man page from

  http://tktable.sourceforge.net/winico/winico.html

you will probably see the point how this is supposed to work.

Another problem is how to write the callback function for mouse clicks
onto the icon. I guess you will have to add the percent substitutions
and register the callback manually, like:

    import Tkinter, Winico
    root = Tkinter.Tk()

    def your_callback(icon_id, message_specifier):
        if message_specifier == "WM_LBUTTONDBLCLK":
            (... do something with icon_id...)
        elif message_specifier == "WM_RBUTTONDOWN":
            (... do something else with icon_id...)

    # register the callback for Tk:
    cmd = (root.register(your_callback), '%i', '%m')

    # create an icon
    icon = Winico.Winico()
    icon_id = icon.createfrom("some.ico")
    icon.taskbar_add(icon_id, callback=cmd, text="Your text here")

I think you see the point, how the percent substitutions are passed to
the callback.

I hope this helps

Michael

PS:
I forwarded this to the list, maybe it is interesting for
other people, too, I hope that's ok.