New Tkinter windows don't get focus on OS X

[Joshua Bronson]

If you try something like:

$ python -m Tkinter -c 'Tkinter._test()'

in Terminal on OS X, you'll notice that the window that is spawned
does not get focus, rather focus remains in Terminal. Furthermore, if
you hit Command+Tab to switch focus to the Python process, you'll
notice that for some reason Python has been placed last in the focus
order, even though it was just spawned by Terminal. This is
undesirable if you're e.g. making a game where stuff happens as soon
as the window is spawned and the player is expected to respond quickly
but can't until she Command+Tabs over or clicks in the unfocused
window. I've googled for this extensively and haven't found a way
around it, so I thought I'd ask here. If there is a more appropriate
place to ask, please let me know.

Thanks,
Josh

 

[Kevin Walzer]

If you try something like:

$ python -m Tkinter -c 'Tkinter._test()'

in Terminal on OS X, you'll notice that the window that is spawned
does not get focus, rather focus remains in Terminal. Furthermore, if
you hit Command+Tab to switch focus to the Python process, you'll
notice that for some reason Python has been placed last in the focus
order, even though it was just spawned by Terminal. This is
undesirable if you're e.g. making a game where stuff happens as soon
as the window is spawned and the player is expected to respond quickly
but can't until she Command+Tabs over or clicks in the unfocused
window. I've googled for this extensively and haven't found a way
around it, so I thought I'd ask here. If there is a more appropriate
place to ask, please let me know.

Thanks,
Josh

Yes, this is standard behavior for OS X. Running an app in Terminal
keeps focus in the Terminal unless you switch by clicking windows. The
Command-Tab behavior is determined by the windowing system, not by a
newly spawned process.

The way around this is to wrap your application up in a standard Mac app
bundle using py2app. The average Mac user isn't going to launch a
Python-based game from the command line.

Kevin

 

[Joshua Bronson]

Hey Kevin,

Thanks for your quick reply.

Yes, this is standard  behavior for OS X. Running an app in Terminal
keeps focus in the Terminal unless you switch by clicking windows.

At first I was puzzled by this, because if you run something like
"open -a TextEdit", TextEdit gets the focus. But then I realized this
must be because of the "open" command. Indeed, if you try running
something like "/Applications/MacPorts/Python\ 2.6/IDLE.app/Contents/
MacOS/IDLE" focus will remain in Terminal.

On the other hand, every other GUI toolkit I've used (e.g. wxPython,
PyQt4, pyglet) does not have this problem. (If you try the basic
example from http://www.wxpython.org/tut-part1.php you'll see what I
mean.) How are these other toolkits able to steal the focus? More
important, is it *possible* to have a Tkinter app steal the focus,
even if it's not the default behavior?

The Command-Tab behavior is determined by the windowing system, not
by a newly spawned process.

Sure, but I've always noticed a correspondence between the focus order
and the order in which an application was spawned. So the conclusion
is that there's just a system-wide inconsistency here in the case of
spawning GUI apps from Terminal.

The way around this is to wrap your application up in a standard Mac app
bundle using py2app. The average Mac user isn't going to launch a
Python-based game from the command line.

True, but it'll still be a lot less painful for me to test my app if I
can get it to steal focus
when launched from the command line. If anyone knows how to do this in
Tkinter, help would be much appreciated.

Thanks,
Josh

 

[Kevin Walzer]

Hi Joshua,

At first I was puzzled by this, because if you run something like
"open -a TextEdit", TextEdit gets the focus. But then I realized this
must be because of the "open" command. Indeed, if you try running
something like "/Applications/MacPorts/Python\ 2.6/IDLE.app/Contents/
MacOS/IDLE" focus will remain in Terminal.
OK...


On the other hand, every other GUI toolkit I've used (e.g. wxPython,
PyQt4, pyglet) does not have this problem. (If you try the basic
example from http://www.wxpython.org/tut-part1.php you'll see what I
mean.) How are these other toolkits able to steal the focus? More
important, is it *possible* to have a Tkinter app steal the focus,
even if it's not the default behavior?

I've confirmed this with wx...not sure why Tk behaves differently.

True, but it'll still be a lot less painful for me to test my app if I
can get it to steal focus
when launched from the command line. If anyone knows how to do this in
Tkinter, help would be much appreciated.

I'm not sure there's a way to do this.

--Kevin

 

[Hendrik van Rooyen]

True, but it'll still be a lot less painful for me to test my app if I
can get it to steal focus
when launched from the command line. If anyone knows how to do this in
Tkinter, help would be much appreciated.

look for widget.focus_force()
and look for widget.grab_set_global()

Yahoo for: Shipman Tkinter "new mexico tech"
for a nice manual, if you do not have it yet.

HTH - Hendrik

 

[eb303]

look for widget.focus_force()
and look for widget.grab_set_global()

Doesn't work. BTW, forcing the focus or setting the grab globally are
usually considered very annoying and I don't know any windowing system
or window manager honouring those.

For the OP: the problem comes from the tcl/tk level. Running a tcl
script just opening a window from the terminal shows the same
behaviour. You might want to forward the question to the tcl guys.

 

[Hendrik van Rooyen]

On Sep 11, 9:14 am, Hendrik van Rooyen <[email protected]>
wrote:

Doesn't work. BTW, forcing the focus or setting the grab globally are
usually considered very annoying and I don't know any windowing system
or window manager honouring those.

I have to confess I have never used the stuff - just remembered seeing it in
the manual and pointed it out.

What does it do?

- Hendrik

 

[eb303]

I have to confess I have never used the stuff - just remembered seeing it in
the manual and pointed it out.

What does it do?

At tcl level, focus_force() and grab_set_global() are translated as
options to the equivalents of focus_set() and grab_set() [1][2]. If
these are not honoured, the options are simply ignored. That's what
seems to happen on Mac OS X. So focus_force() does the same as
focus_set(), and grab_set_global() the same as grab_set(). No use for
the OP's problem...

[1] http://www.tcl.tk/man/tcl8.5/TkCmd/focus.htm
[2] http://www.tcl.tk/man/tcl8.5/TkCmd/grab.htm

 

[Joshua Bronson]

For the OP: the problem comes from the tcl/tk level. Running a tcl
script just opening a window from the terminal shows the same
behaviour. You might want to forward the question to the tcl guys.

Done:
https://sourceforge.net/[email protected]&forum_name=tcl-mac